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{{Short description|Unit of time about as long the orbital period of the Moon}}
{{About|the general concept|the internationally used calendar months|Gregorian calendar#Months}}
A '''month''' is a unit of [[time]], used with [[calendar]]s, that is approximately as long as a natural phase cycle of the [[Moon]]; the words ''month'' and ''Moon'' are [[cognate]]s. The traditional concept of months arose with the cycle of [[Moon phase]]s; such [[lunar month]]s ("lunations") are [[Lunar month#Synodic month|synodic months]] and last approximately 29.53 [[day]]s, making for roughly <!-- CALC: 365.2425/29.53 --> 12.37 such months in one Earth year. From excavated [[tally stick]]s, researchers have deduced that people counted days in relation to the Moon's phases as early as the [[Paleolithic]] age. Synodic months, based on the Moon's [[orbital period]] with respect to the Earth–Sun line, are still the basis of many calendars today and are used to divide the [[year]].
Calendars that developed from the [[Roman calendar]] system, such as the internationally used [[Gregorian calendar]], divide the year into 12 months, each of which lasts between 28 and 31 days. The names of the months were Anglicized from various Latin names and events important to Rome, except for the months 9–12, which are named after the Latin numerals 7–10 (''septem'', ''octo'', ''novem'', and ''decem'') because they were originally the seventh through tenth months in the Roman calendar.<ref name=Macrobius>[[Macrobius]], ''[[Saturnalia]]'', tr. Percival Vaughan Davies (New York: Columbia University Press, 1969), book I, chapters 12–13, pp. 89–95.</ref> In the modern Gregorian calendar, the only month with a variable number of days is the second month, February, which has 29 days during a [[leap year]] and 28 days otherwise.
== Types of months in astronomy ==
{{main|Lunar month}}
The following types of months are mainly of significance in astronomy. Most of them (but not the distinction between sidereal and tropical months) were first recognized in [[Lunar theory#Babylon|Babylonian lunar astronomy]].
# The '''sidereal month''' is defined as the Moon's [[orbital period]] in a non-rotating frame of reference (which on average is equal to its [[rotation period]] in the same frame). It is about 27.32166 days (27&nbsp;days 7&nbsp;hours 43&nbsp;minutes 11.6&nbsp;seconds). It is closely equal to the time it takes the Moon to twice pass a "fixed" [[star]] (different stars give different results because all have a very small [[proper motion]] and are not really fixed in position).
# A '''synodic month''' is the most familiar lunar cycle, defined as the time interval between two consecutive occurrences of a particular phase (such as new moon or full moon) as seen by an observer on Earth. The mean length of the synodic month is 29.53059 days (29 days, 12 hours, 44 minutes, 2.8 seconds). Due to the eccentricity of the lunar orbit around Earth (and to a lesser degree, the Earth's elliptical orbit around the Sun), the length of a synodic month can vary by up to seven hours.
# The '''tropical month''' is the average time for the Moon to pass twice through the same [[equinox]] point of the sky. It is 27.32158 days, very slightly shorter than the sidereal month (27.32166) days, because of [[precession of the equinoxes]].
# An '''anomalistic month''' is the average time the Moon takes to go from [[perigee]] to perigee—the point in the Moon's orbit when it is closest to Earth. An anomalistic month is about 27.55455 days on average.
# The '''draconic month''', draconitic month, or nodal month is the period in which the Moon returns to the same [[lunar node|node]] of its orbit; the nodes are the two points where the Moon's orbit crosses the plane of the Earth's orbit. Its duration is about 27.21222 days on average.
A synodic month is longer than a sidereal month because the Earth-Moon system is orbiting the Sun in the same direction as the Moon is orbiting the Earth.{{Citation needed|date=December 2023|reason=This is a nonobvious proposition.}} The Sun moves eastward with respect to the stars (as does the Moon) and it takes about 2.2 days longer for the Moon to return to the same apparent position with respect to the Sun.
An anomalistic month is longer than a sidereal month because the perigee moves in the same direction as the Moon is orbiting the Earth, one revolution in nine years. Therefore, the Moon takes a little longer to return to perigee than to return to the same star.
A draconic month is shorter than a sidereal month because the nodes move in the opposite direction as the Moon is orbiting the Earth, one revolution in 18.6 years. Therefore, the Moon returns to the same node slightly earlier than it returns to the same star.
== Calendrical consequences ==
{{Further|lunar calendar|lunisolar calendar}}
At the simplest level, most well-known lunar calendars are based on the initial approximation that 2 lunations last 59 [[solar day]]s: a 30-day '''full month''' followed by a 29-day '''hollow month''' — but this is only roughly accurate and regularly needs [[intercalation (timekeeping)|intercalation]] (correction) by a [[leap day]].
Additionally, the synodic month does not fit easily into the [[tropical year|solar (or 'tropical') year]], which makes accurate, rule-based [[lunisolar calendar]]s that combine the two cycles complicated. The most common solution to this problem is the [[Metonic cycle]], which takes advantage of the fact that 235 lunations are approximately 19 tropical years (which add up to not quite 6,940 days): 12 years have 12 lunar months, and 7 years are 13 lunar months long. However, a [[Metonic calendar]] based year will drift against the seasons by about one day every 2 centuries. Metonic calendars include the calendar used in the [[Antikythera Mechanism]] about 21 centuries ago, and the [[Hebrew calendar]].
Alternatively in a pure [[lunar calendar]], years are defined as having always 12 lunations, so a year is 354 or 355 days long: the [[Islamic calendar]] is the prime example.  Consequently, an Islamic year is about 11 days shorter than a solar year and cycles through the seasons in about 33 solar = 34 lunar years: the [[Islamic New Year]] has a different [[Gregorian calendar]] date in each (solar) year.
Purely [[solar calendar]]s often have months which no longer relate to the phase of the Moon, but are based only on the motion of the Sun relative to the equinoxes and solstices, or are purely conventional like in the widely used [[Gregorian calendar]].
The complexity required in an accurate lunisolar calendar may explain why solar calendars have generally replaced lunisolar and lunar calendars for civil use in most societies.
== Months in various calendars ==
=== Beginning of the lunar month ===
The [[Hellenic calendars]], the [[Hebrew calendar|Hebrew Lunisolar calendar]] and the [[Islamic calendar|Islamic Lunar calendar]] started the month with the first appearance of the thin crescent of the [[new moon]].
However, the motion of the Moon in its [[orbit]] is very complicated and its period is not constant. The date and time of this actual observation depends on the exact geographical longitude as well as latitude, atmospheric conditions, the visual acuity of the observers, etc. Therefore, the beginning and lengths of months defined by observation cannot be accurately predicted.
While some like orthodox Islam and the Jewish [[Karaite (Jewish sect)|Karaites]] still rely on actual moon observations, reliance on [[Islamic calendar#Astronomical considerations|astronomical calculations]] and [[Tabular Islamic calendar|tabular methods]] is increasingly common in practice.<ref>{{Cite web |title=Calculations or Sighting for starting an Islamic month |url=http://www.moonsighting.com/calculation-or-sighting.html |url-status=dead |archive-url=https://web.archive.org/web/20170508214424/http://www.moonsighting.com/calculation-or-sighting.html |archive-date=8 May 2017 |access-date=16 April 2017 |website=www.moonsighting.com |df=dmy-all}}</ref><ref>{{Cite web |last=Chraibi |first=Khalid|date=9 April 2021|language=fr |title=Le mois islamique est-il universel ou national ? |url=http://oumma.com/Le-mois-islamique-est-il-universel |website=Oumma}}</ref>
===Ahom calendar===
{{special characters|section}}
There are 12 months and an additional leap year month in the [[Ahom people|Ahom]] [[Sexagenary cycle|sexagenary]] calendar known as Lak-ni.{{sfnp|Phukan Baruah|1964|p=193}}{{sfnp|Kapoor|2021|p=668}} The first month is Duin Shing.{{sfnp|Phukan Baruah|1964|p=193}}
{| class="wikitable"
|-
! No. || Name || Ahom script  || Gregorian month
|-
| 1 || Duin-Shing || 𑜓𑜢𑜤𑜃𑜫 𑜋𑜢𑜂𑜫 || [[November]]-[[December]]
|-
| 2 || Duin-Kam || 𑜓𑜢𑜤𑜃𑜫 𑜀𑜪 || [[December]]-[[January]]
|-
| 3 || Duin-Tsam || 𑜓𑜢𑜤𑜃𑜫 𑜏𑜪 || [[January]]-[[February]]
|-
| 4 || Duin-Shi || 𑜓𑜢𑜤𑜃𑜫  𑜏𑜢 || [[February]]-[[March]]
|-
| 5 || Duin-Ha || 𑜓𑜢𑜤𑜃𑜫 𑜑𑜡 || [[March]]-[[April]]
|-
| 6 || Duin-Rok || 𑜓𑜢𑜤𑜃𑜫 𑜍𑜤𑜀𑜫 || [[April]]-[[May]]
|-
| 7 || Duin-Shit || 𑜓𑜢𑜤𑜃𑜫 𑜋𑜢𑜄𑜫 || [[May]]-[[June]]
|-
| 8 || Duin-paet || 𑜓𑜢𑜤𑜃𑜫 𑜆𑜢𑜤𑜄𑜫 || [[June]]-[[July]]
|-
| 9 || Duin-kauo || 𑜓𑜢𑜤𑜃𑜫 𑜀𑜰𑜫 || [[July]]-[[August]]
|-
| 10 || Duin-sip || 𑜓𑜢𑜤𑜃𑜫 𑜏𑜢𑜆𑜫 || [[August]]-[[September]]
|-
| 11 || Duin-tsip-it || 𑜓𑜢𑜤𑜃𑜫 𑜏𑜢𑜆𑜫 𑜒𑜪𑜄𑜫 || [[September]]-[[October]]
|-
| 12 || Duin-sip-song || 𑜓𑜢𑜤𑜃𑜫 𑜏𑜢𑜆𑜫 𑜁 || [[October]]-[[November]]
|}
=== Roman calendar ===
The [[Roman calendar]] was reformed several times, the last three enduring reforms during historical times. The last three reformed Roman calendars are called the ''Julian'', ''Augustan'', and ''Gregorian''; all had the same number of days in their months. Despite other attempts, the names of the months after the [[Augustan calendar]] reform have persisted, and the number of days in each month (except February) have remained constant since before the [[Julian calendar|Julian reform]]. The [[Gregorian calendar]], like the [[Julian calendar|Roman calendars]] before it, has twelve months, whose [[Anglicized]] names are:
<!--DO NOT abbreviate the names of the months! There is plenty of room for their full names in English. Thanks.-->
:{| class="wikitable sortable"
|- style="vertical-align:bottom;"
! Order !! Name !! Number<br>of days
|-  style="text-align:center;"
|  1
|style="text-align:left;"| '''[[January]]''' || 31
|-  style="text-align:center;"
|  2
|style="text-align:left;"| '''[[February]]'''
| 28<br/>{{small|29 in [[leap year]]s}}
|-  style="text-align:center;"
|  3
|style="text-align:left;"| '''[[March]]''' || 31
|-  style="text-align:center;"
|  4
|style="text-align:left;"| '''[[April]]''' || 30
|-  style="text-align:center;"
|  5
|style="text-align:left;"| '''[[May]]''' || 31
|-  style="text-align:center;"
|  6
|style="text-align:left;"| '''[[June]]''' || 30
|- a style="text-align:center;"
|  7
|style="text-align:left;"| '''[[July]]'''<br/>{{small|formerly ''[[Quinctilis]]''}}
| 31
|-  style="text-align:center;"
|  8
|style="text-align:left;"| '''[[August]]'''<br/>{{small|formerly ''[[Sextilis]]''}}
| 31
|-  style="text-align:center;"
|  9
|style="text-align:left;"| '''[[September]]''' || 30
|-  style="text-align:center;"
| 10
|style="text-align:left;"| '''[[October]]''' || 31
|-  style="text-align:center;"
| 11
|style="text-align:left;"| '''[[November]]''' || 30
|-  style="text-align:center;"
| 12
|style="text-align:left;"| '''[[December]]''' || 31
|}
{{Self reference|One of Wikipedia's sister projects, [[Wiktionary]], provides translations of each of the Gregorian/Julian calendar months into a dozen or more languages. Month-by-month links are provided here: [[wikt:January|January]], [[wikt:February|February]], [[wikt:March|March]], [[wikt:April|April]], [[wikt:May|May]], [[wikt:June|June]], [[wikt:July|July]], [[wikt:August|August]], [[wikt:September|September]], [[wikt:October|October]], [[wikt:November|November]], [[wikt:December|December]].}}
[[File:Month - Knuckles (en).svg|thumb|300px|On top of the knuckles (yellow): 31&nbsp;days<br/>Between the knuckles (blue): 30&nbsp;days<br/>February (red) has 28 or 29&nbsp;days.]]
[[File:Klaviatur-3-en.svg|thumb|300px|The white keys of the musical keyboard correspond to months with 31&nbsp;day months. ('''F''' corresponds to January.)]]
The famous [[mnemonic]] ''[[Thirty days hath September]]'' is a common way of teaching the lengths of the months in the English-speaking world. The knuckles of the four fingers of one's hand and the spaces between them can be used to remember the lengths of the months. By making a fist, each month will be listed as one proceeds across the hand. All months landing on a knuckle are 31&nbsp;days long and those landing between them are 30&nbsp;days long, with variable February being the remembered exception. When the knuckle of the index finger is reached (July), go over to the first knuckle on the other fist, held next to the first (or go back to the first knuckle) and continue with August. This physical mnemonic has been taught to primary school students for many decades, if not centuries.<ref>{{cite web |year=1997 |title=Days in each month |website=Mnemonics to Improve Memory |publisher=EUdesign |url=http://www.eudesign.com/mnems/dayspcm.htm |access-date=8 August 2018}}</ref><ref>{{cite book |title=The Boy Mechanic: A handy calendar |year=1913 |volume=1 |publisher=[[Project Gutenberg]] |via=Full Books |url=http://www.fullbooks.com/The-Boy-Mechanic-Volume-17.html}}</ref>
This cyclical pattern of month lengths matches the [[musical keyboard]] alternation of wide white keys (31&nbsp;days) and narrow black keys (30&nbsp;days). The note '''F''' corresponds to '''January''', the note '''F{{sup|{{music|#}}}}''' corresponds to '''February''', the exceptional 28–29&nbsp;day month, and so on.
==== Numerical relations ====
The mean month-length in the Gregorian calendar is 30.436875&nbsp;days.
Any five consecutive months, that do not include February, contain 153&nbsp;days.
==== Calends, nones, and ides ====
Months in the pre-Julian [[Roman calendar]] included:
* ''[[Intercalaris]]'' an [[intercalary month]] occasionally embedded into February, to realign the calendar.
* ''[[Quintilis]]'', later renamed to ''Julius'' in honour of [[Julius Caesar]].
* ''[[Sextilis]]'', later renamed to ''Augustus'' in honour of [[Augustus]].
The Romans divided their months into three parts, which they called the ''calends'', the ''nones'', and the ''ides''. Their system is somewhat intricate.
The '''[[ides (calendar)|ides]]''' occur on the thirteenth day in eight of the months, but in March, May, July, and October, they occur on the fifteenth. The '''[[Roman calendar#Months|nones]]''' always occur 8&nbsp;days (one Roman 'week') before the ides, i.e., on the fifth or the seventh. The '''[[calends]]''' are always the first day of the month,{{efn|More precisely, the [[calends]] were when the name of a month first began being used when referring to dates. Instead of counting the number of days elapsed, the Romans used a [[countdown]] to number their dates. See the article ''[[Roman calendar]]'' for a more detailed explanation.}} and before Julius Caesar's reform fell sixteen days (two Roman weeks) after the ides (except the ides of February and the intercalary month).
==== Relations between dates, weekdays, and months in the Gregorian calendar ====
Within a month, the following dates fall on the same day of the week:
* '''01, 08, 15, 22, and 29''' (e.g., in January 2022, all these dates fell on a Saturday)
* '''02, 09, 16, 23, and 30''' (e.g., in January 2022, all these dates fell on a Sunday)
* '''03, 10, 17, 24, and 31''' (e.g., in January 2022, all these dates fell on a Monday)
* '''04, 11, 18, and 25''' (e.g., in January 2022, all these dates fell on a Tuesday)
* '''05, 12, 19, and 26''' (e.g., in January 2022, all these dates fell on a Wednesday)
* '''06, 13, 20, and 27''' (e.g., in January 2022, all these dates fell on a Thursday)
* '''07, 14, 21, and 28''' (e.g., in January 2022, all these dates fell on a Friday)
Some months have the same date/weekday structure.
In a non-leap year:
* '''January/October''' (e.g., in 2022, they began on a Saturday)
* '''February/March/November''' (e.g., in 2022, they began on a Tuesday)
* '''April/July''' (e.g., in 2022, they began on a Friday)
* '''September/December''' (e.g., in 2022, they began on a Thursday)
*  '''1 January''' and '''31 December''' fall on the same weekday (e.g. in 2022 on a Saturday)
In a leap year:
* '''February/August''' (e.g., in 2020, they began on a Saturday)
* '''March/November''' (e.g., in 2020, they began on a Sunday)
* '''January/April/July''' (e.g., in 2020, they began on a Wednesday)
* '''September/December''' (e.g., in 2020, they began on a Tuesday)
* '''29 February''' (the leap day) falls on the same weekday like 1, 8, 15, 22 February and 1 August (see above; e.g. in 2020 on a Saturday)
=== Hebrew calendar ===
The [[Hebrew calendar]] has 12 or 13 months.
# [[Nisan]], 30 days ניסן
# [[Iyar]], 30 days אייר
# [[Sivan]], 30 days סיון
# [[Tammuz (Hebrew month)|Tammuz]], 29 days תמוז
# [[Av (month)|Av]], 30 days אב
# [[Elul]], 29 days אלול
# [[Tishri]], 30 days תשרי
# [[Marcheshvan]], 29/30 days מַרְחֶשְׁוָן
# [[Kislev]], 30/29 days כסלו
# [[Tevet]], 29 days טבת
# [[Shevat]], 30 days שבט
# [[Adar 1]], 30 days, [[Intercalation (timekeeping)|intercalary]] month אדר א
# [[Adar 2]], 29 days אדר ב
Adar 1 is only added 7 times in 19 years. In ordinary years, Adar 2 is simply called Adar.
=== Islamic calendar ===
There are also twelve months in the Islamic calendar. They are named as follows:
# [[Muharram]] (Restricted/sacred) محرّم
# [[Safar]] (Empty/Yellow) صفر
# [[Rabi' al-awwal|Rabī' al-Awwal]]/Rabi' I (First Spring) ربيع الأول
# [[Rabi' al-Thani|Rabī' ath-Thānī]]/Rabi' al-Aakhir/Rabi' II (Second spring or Last spring) ربيع الآخر أو ربيع الثاني
# [[Jumada al-Awwal]]/Jumaada I (First Freeze) جمادى الأول
# [[Jumada al-Thani|Jumada ath-Thānī]] or Jumādā al-Thānī/Jumādā II (Second Freeze or Last Freeze) جمادى الآخر أو جمادى الثاني
# [[Rajab]] (To Respect) رجب
# [[Sha'ban|Sha'bān]] (To Spread and Distribute) شعبان
# [[Ramadan|Ramadān]] (Parched Thirst) رمضان
# [[Shawwal|Shawwāl]] (To Be Light and Vigorous) شوّال
# [[Dhu al-Qi'dah]] (The Master of Truce) ذو القعدة
# [[Dhu al-Hijjah]] (The Possessor of Hajj) ذو الحجة
See [[Islamic calendar]] for more information on the Islamic calendar.
=== Arabic calendar ===
{{main|Arabic names of calendar months}}
{| class="wikitable"
|-
!colspan=2| Gregorian month
!colspan=2| Arabic month
|-
| [[January]] || يناير ||  كانون الثاني || Kanun Al-Thani
|-
| [[February]] || فبراير || شباط || Shebat
|-
| [[March]] ||  مارس || اذار || Adhar
|-
| [[April]] || ابريل || نيسان || Nisan
|-
| [[May]] || مايو || أيّار || Ayyar
|-
| [[June]] ||يونيو || حزيران || Ḩazayran
|-
| [[July]] || يوليو || تمّوز || Tammuz
|-
| [[August]] || أغسطس || اَب || ʕAb
|-
| [[September]] || سبتمبر || أيلول || Aylul
|-
| [[October]] || أكتوبر || تشرين الأول || Tishrin Al-Awwal
|-
| [[November]] || نوفمبر || تشرين الثاني || Tishrin Al-Thani
|-
| [[December]] || ديسمبر || كانون الأول || Kanun Al-Awwal
|}
=== Hindu calendar ===
The [[Hindu calendar]] has various systems of naming the months. The months in the lunar calendar are:
{| class="wikitable"
|-
!  !! Sanskrit name !! Tamil name !! Telugu name!! Nepali name!! Assamese name
|-
| 1 || [[Vaishakha|Vaiśākha]] (वैशाख) || Vaikasi (வைகாசி) || Vaisaakhamu (వైశాఖము)|| [[Baisakh]] (बैशाख) ||Bahāg (বহাগ)
|-
| 2 || [[Jyeshtha (month)|Jyeṣṭha]] (ज्येष्ठ) || Aani (ஆனி) || Jyeshttamu (జ్యేష్ఠము)|| [[Jestha|Jeth]] (जेष्ठ/जेठ)|| Jeth (জেঠ)
|-
|3||[[Ashadha]] (आषाढ) ||  Aadi (ஆடி) || Aashaadhamu (ఆషాఢము)|| [[Ashadha|Asaar]] (आषाढ/असार)|| Āsār/Āhār (আষাঢ়/আহাৰ)
|-
|4||[[Śrāvaṇa]] (श्रावण) || [[Aavani]] (ஆவணி) || Sraavanamu (శ్రావణము)||  [[Śrāvaṇa|Saaoon]] (श्रावण/साउन)||Sāoon (শাওণ)
|-
|5|| [[Bhadrapada]] (भाद्रपद) || Purratasi (புரட்டாசி) || Bhaadhrapadamu (భాద్రపదము)|| [[Bhadra (Nepali calendar)|Bhadau]] (भाद्र|भदौ)||Bhādo (ভাদ)
|-
|6||[[Aashvina|Āśvina]] (अश्विन) ||  Aiypasi (ஐப்பசி) || Aasveeyujamu (ఆశ్వయుజము)||[[Aashvina |Asoj]] (आश्विन/असोज) ||Āhin (আহিন)
|-
|7|| [[Kaartika|Kārtika]] (कार्तिक/कात्तिक) || Kaarthigai (கார்த்திகை) || Kaarthikamu (కార్తీకము)|| [[ Kaartika|Kaattick]](कार्तिक/ कात्तिक) ||Kāti (কাতি)
|-
|8|| [[Maargashiirsha|Mārgaśīrṣa]] (मार्गशीर्ष) || [[Maargazhi]] (மார்கழி) || Maargaseershamu	(మార్గశిరము)|| [[Mangsir]] (मार्ग/मंसिर) ||Āghun (আঘোণ)
|-
|9|| [[Pausha|Pauṣa]] (पौष) || Thai (தை) || Pushyamu (పుష్యము)|| [[Poush|Push]] (पौष/पुष/पूस)|| Puh (পুহ)
|-
|10|| [[Maagha|Māgha]] (माघ) || [[Maagha|Maasi]] (மாசி) || Maaghamu (మాఘము)|| [[Magh (Nepali calendar)|Magh]] (माघ) || Māgh (মাঘ)
|-
|11||[[Phaalguna|Phālguna]] (फाल्गुन) || [[Panguni]] (பங்குனி) || Phaalgunamu (ఫాల్గుణము)|| [[Phaalguna|Faagoon]] (फाल्गुन/फागुन)|| Fāgoon (ফাগুণ)
|-
| 12|| [[Chaitra]] (चैत्र) ||  Chitirai (சித்திரை) || Chaithramu	(చైత్రము)|| [[Chaitra|Chait]] (चैत्र/चैत) || Chot (চ'ত)
|}
These are also the names used in the [[Indian national calendar]] for the newly redefined months. Purushottam Maas or Adhik Maas ([[Romanisation of Hindi|translit.]] ''{{lang|hi-Latn|adhika}}'' = 'extra', ''{{lang|hi-Latn|māsa}}'' = 'month') is an extra month in the [[Hindu calendar]] that is inserted to keep the [[Lunar calendar|lunar]] and [[solar calendar]]s aligned. "Purushottam" is an epithet of [[Vishnu]], to whom the month is dedicated.
The names in the solar calendar are just the names of the [[zodiac]] sign in which the sun travels. They are
<!-- surely this table can be done differently/better? -->
# [[Aries (constellation)|Mesha]]
# [[Taurus (constellation)|Vrishabha]]
# [[Gemini (constellation)|Mithuna]]
# [[Cancer (constellation)|Kataka]]
# [[Leo (constellation)|Simha]]
# [[Virgo (constellation)|Kanyaa]]
# [[Libra (constellation)|Tulaa]]
# [[Scorpius (constellation)|Vrishcika]]
# [[Sagittarius (constellation)|Dhanus]]
# [[Capricornus (constellation)|Makara]]
# [[Aquarius (constellation)|Kumbha]]
# [[Pisces (constellation)|Miina]]
=== Baháʼí calendar ===
The [[Baháʼí calendar]] is the calendar used by the [[Baháʼí Faith]]. It is a solar calendar with regular years of 365 days, and [[leap year]]s of 366 days. Years are composed of 19 months of 19 days each (361 days), plus an extra period of "[[Ayyám-i-Há|Intercalary Days]]" (4 in regular and 5 in leap years).{{sfnp|Esslemont|1980|pages=178{{ndash}}179}} The months are named after the attributes of God. Days of the year begin and end at sundown.{{sfnp|Esslemont|1980|pages=178{{ndash}}179}}
=== Iranian calendar (Persian calendar) ===
The [[Iranian calendar|Iranian / Persian calendar]], currently used in [[Iran]], also has 12 months. The [[Persian language|Persian]] names are included in the parentheses. It begins on the northern Spring equinox.
# [[Farvardin]] (31 days, فروردین)
# [[Ordibehesht]] (31 days, اردیبهشت)
# [[Khordad]] (31 days, خرداد)
# [[Tir (month)|Tir]] (31 days, تیر)
# [[Mordad]] (31 days, مرداد)
# [[Shahrivar]] (31 days, شهریور)
# [[Mehr (month)|Mehr]] (30 days, مهر)
# [[Aban]] (30 days, آبان)
# [[Azar]] (30 days, آذر)
# [[Dey (month)|Dey]] (30 days, دی)
# [[Bahman]] (30 days, بهمن)
# [[Esfand]] (29 days- 30 days in leap year, اسفند)
=== Reformed Bengali calendar ===
The [[Bengali calendar]], used in [[Bangladesh]], follows solar months and it has six seasons. The months and seasons in the calendar are:
{| class="wikitable"
! No. || Name ([[Bengali language|Bengali]]) || Name ([[Sylheti language|Sylheti]]) || Name ([[Rohingya language|Rohingya]]) ||Season || Days || Roman months
|-
| 1 || [[Boishakh|Boishakh (বৈশাখ)]] || [[Boishakh]] || [[Boishakh|Boicák]] ||[[Summer|Grishmo (গ্রীষ্ম)]] || 31 || 14 April – May
|-
| 2 || [[Joishtho|Joishtho (জ্যৈষ্ঠ)]] || [[Joishtho|Zoit]] || [[Joishtho|Zeth]] || [[Summer|Grishmo (গ্রীষ্ম)]] || 31 || May – June
|-
| 3 || [[Asharh|Asharh (আষাঢ়)]] || [[Asharh|Aaŗ]] || [[Asharh|Acár]] || [[Wet season|Borsha (বর্ষা)]] || 31 || June – July
|-
| 4 || [[Srabon|Shrabon (শ্রাবণ)]] || [[Srabon|Haon]] || [[Srabon|Cón]] || [[Wet season|Borsha (বর্ষা)]] || 31 || July – August
|-
| 5 || [[Bhadro|Bhadro (ভাদ্র)]] || [[Bhadro|Bhado]] || [[Bhadro|Bádo]] || [[Autumn|Shorot (শরৎ)]] || 31 || August – September
|-
| 6 || [[Ashvin|Aashin (আশ্বিন)]] || [[Ashvin|Ashin]] || [[Ashvin|Acín]] || [[Autumn|Shorot (শরৎ)]] || 30 || September – October
|-
| 7 || [[Kartik (month)|Kartik (কার্তিক)]] || [[Kartik (month)|Khati]] || [[Kartik (month)|Hati]] || [[Dry season|Hemonto(হেমন্ত)]] || 30 || October – November
|-
| 8 || [[Ogrohayon|Ogrohayon (অগ্রহায়ণ)]] || [[Ogrohayon|Aghon]] || [[Ogrohayon|Óon]] || [[Dry season|Hemonto(হেমন্ত)]] || 30 || November – December
|-
| 9 || [[Poush|Poush (পৌষ)]] || [[Poush|Phush]] || [[Poush|Fuc]] || [[Winter|Sheet (শীত)]] || 30 || December – January
|-
| 10 || [[Magh (Bengali calendar)|Magh (মাঘ)]] || [[Magh (Bengali calendar)|Magh (মাঘ)]] || [[Magh (Bengali calendar)|Mak]] || [[Winter|Sheet (শীত)]] || 30 || January – February
|-
| 11 || [[Falgun|Falgun (ফাল্গুন)]] || [[Falgun|Fagun]] || [[Falgun|Fóon]] || [[Spring (season)|Boshonto (বসন্ত)]] || 30 (31 in leap years) || February – March
|-
| 12 || [[Choitro|Choitro (চৈত্র)]] || [[Choitro|Soit]] || [[Choitro|Soit]] || [[Spring (season)|Boshonto (বসন্ত)]] || 30 || March – April
|}
=== Nanakshahi calendar ===
The months in the [[Nanakshahi calendar]] are:<ref>{{Cite web |year=2007 |title=What is the Sikh Nanakshahi calendar |url=http://www.allaboutsikhs.com/sikh-way-of-life/the-sikh-nanakshahi-calendar-3.html |archive-url=https://web.archive.org/web/20080510183956/http://www.allaboutsikhs.com/sikh-way-of-life/the-sikh-nanakshahi-calendar-3.html |archive-date=10 May 2008 |access-date=9 May 2008 |website=All About Sikhs |publisher=Gateway to Sikhism}}</ref>
{| class="wikitable"
!No. || Name || [[Punjabi language|Punjabi]] || Days || Julian months
|-
| 1 || [[Chet (month)|Chet]] || ਚੇਤ || 31 || 14 March – 13 April
|-
| 2 || [[Vaisakh]] || ਵੈਸਾਖ || 31 || 14 April – 14 May
|-
| 3 || [[Jeth]] || ਜੇਠ || 31 || 15 May – 14 June
|-
| 4 || [[Harh]] || ਹਾੜ || 31 || 15 June – 15 July
|-
| 5 || [[Sawan]] || ਸਾਵਣ || 31 || 16 July – 15 August
|-
| 6 || [[Bhadon]] || ਭਾਦੋਂ || 30 || 16 August – 14 September
|-
| 7 || [[Assu]] || ਅੱਸੂ || 30 || 15 September – 14 October
|-
| 8 || [[Katak]] || ਕੱਤਕ || 30 || 15 October – 13 November
|-
| 9 || [[Maghar (month)|Maghar]] || ਮੱਘਰ || 30 || 14 November – 13 December
|-
| 10 || [[Poh]] || ਪੋਹ || 30 || 14 December – 12 January
|-
| 11 || [[Magh (Sikh calendar)|Magh]] || ਮਾਘ || 30 || 13 January – 11 February
|-
| 12 || [[Phagun]] || ਫੱਗਣ || 30/31 || 12 February – 13 March
|}
=== Khmer calendar ===
Different from the Hindu calendar, the Khmer calendar consists of both a lunar calendar and a solar calendar. The solar is used more commonly than the lunar calendar.
{|class="wikitable"
|-
!scope="col" colspan="4"| Gregorian month
!scope="col" rowspan="2"| Meaning
!scope="col" rowspan="2"| Zodiac sign
|-
!scope="col"| English
!scope="col"| Khmer
!scope="col"| UNGEGN
!scope="col"| ALA-LC
|-
| January || មករា || Môkâréa || Makarā || មករ (UNGEGN: ''môkâr'', ALA-LC: ''makar''); "naga"
|[[Capricorn (astrology)|Capricorn]]
|-
| February || កុម្ភៈ || Kŏmpheă || Kumbhà || ក្អម (UNGEGN: ''k'âm'', ALA-LC: ''kʿʹam''); "clay pitcher"
|[[Aquarius (astrology)|Aquarius]]
|-
| March || មិនា/មីនា || Mĭnéa/Minéa || Minā/Mīnā || ត្រី (UNGEGN: ''trei'', ALA-LC: trī); "fish" or "three/third"
|[[Pisces (astrology)|Pisces]]
|-
| April || មេសា || Mésa || Mesā || ចៀម (UNGEGN: ''chiĕm'', ALA-LC: ''ciam''); "sheep"
|[[Aries (astrology)|Aries]]
|-
| May || ឧសភា || Ŭsâphéa || Usabhā || គោឈ្មោល (UNGEGN: ''koŭ chhmoŭl'', ALA-LC: ''go jhmol''); "bull"
|[[Taurus (astrology)|Taurus]]
|-
| June || មិថុនា || Mĭthŏnéa || Mithunā || គូ (UNGEGN: ''ku'', ALA-LC: ''gū''); "couple"
|[[Gemini (astrology)|Gemini]]
|-
| July || កក្កដា || Kâkkâda || Kakkaṭā || ក្ដាម (UNGEGN: ''kdam'', ALA-LC: ''kṭām''); "crab"
|[[Cancer (astrology)|Cancer]]
|-
| August || សីហា || Seiha || Sīhā || សីហៈ (UNGEGN: ''seihă'', ALA-LC: ''sīhà''); "lion"
|[[Leo (astrology)|Leo]]
|-
| September || កញ្ញា || Kânhnhéa || Kaññā || ក្រមុំ (UNGEGN: ''krâmŭm'', ALA-LC: ''kramuṃ''); "maiden"
|[[Virgo (astrology)|Virgo]]
|-
| October || តុលា || Tŏléa || Tulā || ជញ្ជីង (UNGEGN: ''chônhching'', ALA-LC: ''jañjīng''); "scales"
|[[Libra (astrology)|Libra]]
|-
| November || វិច្ឆិកា || Vĭchchhĕka || Vicchikā || ខ្ទួយ (UNGEGN: ''khtuŏy'', ALA-LC: ''khtuay''); "scorpion"
|[[Scorpio (astrology)|Scorpio]]
|-
| December || ធ្នូ || Thnu || Dhnū || ធ្នូ (UNGEGN: ''thnu'', ALA-LC: ''dhnū''); "bow", "arc"
|[[Sagittarius (astrology)|Sagittarius]]
|}
The Khmer lunar calendar most often contains 12 months; however, the eighth month is repeated (as a "leap month") every two or three years, making 13 months instead of 12.<ref>{{Cite web |title=Khmer Chankeate Calendar |url=http://www.cam-cc.org/calendar/chhankitek.php |access-date=8 August 2018 |website=Cambodian Coordinating Council}}</ref> Each lunar month has 29 or 30 days. The year normally has then 354 or 384 days (when an intercalary month is added), but the calendar follows the rules of the Gregorian calendar to determine leap years and add a lead day to one month, so the Khmer lunar year may have a total of 354, 355, 384 or 385 days.
{|class="wikitable"
|-
!scope="col" rowspan="2"| No.
!scope="col" colspan="3"| Khmer month
|-
!scope="col"| Khmer
!scope="col"| UNGEGN
!scope="col"| ALA-LC
|-
| 1 || មិគសិរ || Mĭkôsĕr || Migasir
|-
| 2 || បុស្ស || Bŏss || Puss
|-
| 3 || មាឃ || Méakh || Māgh
|-
| 4 || ផល្គុន || Phâlkŭn || Phalgun
|-
| 5 || ចេត្រ || Chétr || Cetr
|-
| 6 || វិសាខ/ពិសាខ || Vĭsakh/Pĭsakh || Visākh/Bisākh
|-
| 7 || ជេស្ឋ || Chésth || Jesṭh
|-
| 8<br /> (8a, 8b) || ឤសាឍ<br />(បឋមសាឍ, ទុតិយាសាឍ) || Asath<br />(Bâthâmôsath, Tŭtĕyéasath) || ʿʹāsāḍh (Paṭhamasāḍh, Dutiyāsāḍh)
|-
| 9 || ស្រាពណ៍ || Srapôn || Srābaṇ ̊
|-
| 10 || ភទ្របទ || Phôtrôbât || Bhadrapad
|-
| 11 || អស្សុជ || Âssŏch || ʿʹassuj
|-
| 12 || កត្តិក || Kâtdĕk || Katṭik
|}
=== Thai calendar ===
{{main|Thai solar calendar|Thai lunar calendar}}
{|class="wikitable"
|-
!English name !! Thai name !! Abbr. !! Transcription !! Sanskrit word !! Zodiac sign
|-
|January || มกราคม ||ม.ค.|| mokarakhom || makara "sea-monster" || [[Capricorn (astrology)|Capricorn]]
|-
|February || กุมภาพันธ์ ||ก.พ.|| kumphaphan || kumbha "pitcher, water-pot" || [[Aquarius (astrology)|Aquarius]]
|-
|March || มีนาคม ||มี.ค.|| minakhom || mīna "(a specific kind of) fish" || [[Pisces (astrology)|Pisces]]
|-
|April || เมษายน ||เม.ย.|| mesayon || meṣa "ram" || [[Aries (astrology)|Aries]]
|-
|May || พฤษภาคม ||พ.ค.|| phruetsaphakhom || vṛṣabha "bull" || [[Taurus (astrology)|Taurus]]
|-
|June || มิถุนายน ||มิ.ย.|| mithunayon || mithuna "a pair" || [[Gemini (astrology)|Gemini]]
|-
|July || กรกฎาคม ||ก.ค.|| karakadakhom || karkaṭa "crab" || [[Cancer (astrology)|Cancer]]
|-
|August || สิงหาคม ||ส.ค.|| singhakhom || siṃha "lion" || [[Leo (astrology)|Leo]]
|-
|September || กันยายน ||ก.ย.||kanyayon || kanyā "girl" || [[Virgo (astrology)|Virgo]]
|-
|October || ตุลาคม ||ต.ค.|| tulakhom || tulā "balance" || [[Libra (astrology)|Libra]]
|-
|November || พฤศจิกายน ||พ.ย.|| phruetsachikayon || vṛścika "scorpion" || [[Scorpio (astrology)|Scorpio]]
|-
|December || ธันวาคม ||ธ.ค.|| thanwakhom || dhanu "bow, arc" || [[Sagittarius (astrology)|Sagittarius]]
|}
===Tongan calendar===
The Tongan calendar is based on the cycles of the Moon around the Earth in one year. The months are:
# Liha Mu'a
# Liha Mui
# Vai Mu'a
# Vai Mui
# Faka'afu Mo'ui
# Faka'afu Mate
# Hilinga Kelekele
# Hilinga Mea'a
# 'Ao'ao
# Fu'ufu'unekinanga
# 'Uluenga
# Tanumanga
# 'O'oamofanongo
=== Pingelapese ===
[[Pingelapese language|Pingelapese]], a language from [[Micronesia]], also uses a lunar calendar. There are 12 months associated with their calendar. The Moon first appears in March,{{clarify|This doesn't make sense since 'hundreds of years and many generations' ago, the concept of 'March' was unknown.|date=February 2021}} they name this month ''Kahlek''. This system has been used for hundreds of years and throughout many generations. This calendar is cyclical and relies on the position and shape of the Moon.<ref>{{Cite book |last=Solomon |first=Stenson |title=Pingelap Non-Sacred Knowledge |publisher=Historic Preservation Fund Grant Department of Land and Natural Resources |year=2009}}</ref>
=== Kollam era ([[Malayalam]]) calendar ===
{{main|Kollam era}}
{|class="wikitable"
|-
!Malayalam name !! Transliteration !! Concurrent Gregorian months !!  Sanskrit word and meaning !! Zodiac sign
|-
|ചിങ്ങം || chi-ngnga-m || August–September || simha "lion" || [[Leo (astrology)|Leo]]
|-
|കന്നി || ka-nni ||September–October|| kanyā "girl" || [[Virgo (astrology)|Virgo]]
|-
|തുലാം || thu-lā-m|| October–November || tulā "balance" || [[Libra (astrology)|Libra]]
|-
|വൃശ്ചികം || vRSh-chi-ka-m|| November–December || vṛścika "scorpion" || [[Scorpio (astrology)|Scorpio]]
|-
|ധനു || dha-nu || December–January || dhanu "bow, arc" || [[Sagittarius (astrology)|Sagittarius]]
|-
|മകരം || ma-ka-ra-m ||January–February ||mokara "sea-monster"|| [[Capricorn (astrology)|Capricorn]]
|-
|കുംഭം || kum-bha-m ||February–March ||kumbha "pitcher, water-pot" || [[Aquarius (astrology)|Aquarius]]
|-
|മീനം || mee-na-m ||March–April || mīna "(a specific kind of) fish" || [[Pisces (astrology)|Pisces]]
|-
|മേടം || mE-Da-m ||April–May ||meṣa "ram" || [[Aries (astrology)|Aries]]
|-
|ഇടവം || i-Ta-va-m ||May – June || vṛṣabha "bull" || [[Taurus (astrology)|Taurus]]
|-
|മിഥുനം || mi-thu-na-m ||June–July ||mithuna "a pair" || [[Gemini (astrology)|Gemini]]
|-
|കർക്കടകം || kar-kka-Ta-ka-m ||July–August ||karkaṭa "crab" || [[Cancer (astrology)|Cancer]]
|}
=== Sinhalese calendar ===
The Sinhalese calendar is the [[Buddhist calendar]] in [[Sri Lanka]] with [[Sinhala language|Sinhala]] names. Each full moon [[Poya]] day marks the start of a Buddhist lunar month.<ref>{{Cite web |title=Sri Lanka – Festival Calendar |url=http://premlanka.com/festivals.html |access-date=8 August 2018 |website=Premlanka Hotel |publisher=Curlew Communications Ltd}}</ref> The first month is Bak.<ref>{{Cite web |title=The Significance of Poya |url=http://www.lankalibrary.com/Bud/poya2.htm |access-date=8 August 2018 |website=Lanka Library}}</ref>
# Duruthu (දුරුතු)
# Navam (නවම්)
# Mædin (මැදින්)
# Bak (බක්)
# Vesak (වෙසක්)
# Poson (පොසොන්)
# Æsala (ඇසල)
# Nikini (නිකිණි)
# Binara (බිනර)
# Vap (වප්)
# Il (iL) (ඉල්)
# Unduvap (උඳුවප්)
=== Germanic calendar ===
{{main|Germanic calendar}}
The old Icelandic calendar is not in official use anymore, but some Icelandic holidays and annual feasts are still calculated from it. It has 12 months, broken down into two groups of six often termed "winter months" and "summer months". The calendar is peculiar in that the months always start on the same [[weekday]] rather than on the same [[calendar date|date]]. Hence Þorri always starts on a Friday sometime between January 22 and January 28 ''<small>([[Julian calendar|Old style]]: January 9 to January 15)</small>'', Góa always starts on a Sunday between February 21 and February 27 ''<small>([[Julian calendar|Old style]]: February 8 to February 14)</small>''.
* Skammdegi ("Short days")
# Gormánuður (mid-October – mid-November, "slaughter month" or "[[Gór]]'s month")
# Ýlir (mid-November – mid-December, "[[Yule]] month")
# Mörsugur (mid-December – mid-January, "fat sucking month")
# Þorri (mid-January – mid-February, "frozen snow month")
# Góa (mid-February – mid-March, "Góa's month, see [[Nór]]")
# Einmánuður (mid-March – mid-April, "lone" or "single month")
* Náttleysi ("Nightless days")
# Harpa (mid-April – mid-May, Harpa is a female name, probably a forgotten goddess, first day of Harpa is celebrated as [[Sumardagurinn fyrsti]] – first day of summer)
# Skerpla (mid-May – mid-June, another forgotten goddess)
# Sólmánuður (mid-June – mid-July, "[[sun]] month")
# Heyannir (mid-July – mid-August, "[[hay]] business month")
# Tvímánuður (mid-August – mid-September, "two" or "second month")
# Haustmánuður (mid-September – mid-October, "autumn month")
=== Old Georgian calendar ===
{{main|Georgian calendar}}
{| class="wikitable"
|-
!Month
!Georgian month name
!Transliteration
!Georgian other names
!Transliteration
|- align=center
| [[January]] ||bgcolor="#DDDDFF"| აპნისი, აპანი || Apnisi, Apani||bgcolor="#DDDDFF"|&nbsp;||&nbsp;
|- align=center
| [[February]] ||bgcolor="#DDDDFF"| სურწყუნისი || Surtskunisi||bgcolor="#DDDDFF"| განცხადებისთვე|| Gantskhadebistve
|- align=center
| [[March]] ||bgcolor="#DDDDFF"| მირკანი || Mirkani ||bgcolor="#DDDDFF"| &nbsp;||&nbsp;
|- align=center
| [[April]] ||bgcolor="#DDDDFF"| იგრიკა || Igrika ||bgcolor="#DDDDFF"| &nbsp; ||&nbsp;
|- align=center
| [[May]] ||bgcolor="#DDDDFF"| ვარდობისა || Vardobisa ||bgcolor="#DDDDFF"|ვარდობისთვე || Vardobistve
|- align=center
| [[June]] ||bgcolor="#DDDDFF"| მარიალისა|| Marialisa ||bgcolor="#DDDDFF"| თიბათვე, ივანობისთვე || Tibatve, Ivanobistve
|- align=center
| [[July]] ||bgcolor="#DDDDFF"| თიბისა || Tibisa ||bgcolor="#DDDDFF"|მკათათვე, კვირიკობისთვე || Mkatatve, Kvirikobistve
|- align=center
| [[August]] ||bgcolor="#DDDDFF"| ქველთობისა || Kveltobisa||bgcolor="#DDDDFF"|მარიამობისთვე || Mariamobistve
|- align=center
| [[September]] ||bgcolor="#DDDDFF"| ახალწლისა || Akhaltslisa ||bgcolor="#DDDDFF"| ენკენისთვე || Enkenistve
|- align=center
| [[October]] ||bgcolor="#DDDDFF"| სთვლისა || Stvlisa||bgcolor="#DDDDFF"| ღვინობისთვე || Gvinobistve
|- align=center
| [[November]] ||bgcolor="#DDDDFF"| ტირისკონი || Tiriskoni||bgcolor="#DDDDFF"|  გიორგობისთვე, ჭინკობისთვე ||Giorgobistve, Chinkobistve
|- align=center
| [[December]] ||bgcolor="#DDDDFF"| ტირისდენი || Tirisdeni ||bgcolor="#DDDDFF"| ქრისტეშობისთვე ||Kristeshobistve
|}
'''<small>*NOTE:</small>''' ''New Year in ancient [[Georgia (country)|Georgia]] started from September.''
=== Old Swedish calendar ===
# Torsmånad (January, 'Torre's month' (ancient god))
# Göjemånad (February, 'Goe's month' (ancient goddess))
# Vårmånad (March, 'Spring month')
# Gräsmånad (April, 'Grass month')
# Blomstermånad (May, 'Bloom month')
# Sommarmånad (June, 'Summer month')
# Hömånad (July, 'Hay month')
# Skördemånad, Rötmånad (August, 'Harvest month' or 'Rot month')
# Höstmånad (September, 'Autumn month')
# Slaktmånad (October, 'Slaughter month')
# Vintermånad (November, 'Winter month')
# Julmånad (December, 'Christmas month')
=== Old English calendar ===
Like the Old Norse calendar, the [[Anglo-Saxons]] had their own calendar before they were [[Christianized]] which reflected native traditions and deities. These months were attested by [[Bede]] in his works ''On Chronology'' and ''[[The Reckoning of Time]]'' written in the 8th&nbsp;century.{{sfnp|Newton|2000}} His [[Old English]] month names are probably written as pronounced in Bede's native [[Northumbrian dialect]]. The months were named after the Moon; the new moon marking the end of an old month and start of a new month; the [[full moon]] occurring in the middle of the month, after which the whole month took its name.
:{| class="wikitable"
|+ [[Old English]] month names from [[Bede]]'s ''[[The Reckoning of Time]]''
|-
! Year<br/> order
! Northumbrian<br/> Old English
! Modern English<br/> transliteration
! Roman<br/> equivalent
|- style="vertical-align:top;"
|style="text-align:center;"|  1
| [[Ġēolamonaþ|Æfterra-ġēola mōnaþ]] || “After-[[Yule]] month”
| January
|- style="vertical-align:top;"
|style="text-align:center;"|  2
| [[Solmōnaþ|Sol-mōnaþ]] || “Sol month”
| February
|- style="vertical-align:top;"
|style="text-align:center;"|  3
| [[Hreðmōnaþ|Hrēð-mōnaþ]] || “[[Hretha|Hreth]] month”
| March
|- style="vertical-align:top;"
|style="text-align:center;"|  4
| [[Ēosturmōnaþ|Ēostur-mōnaþ]] || “[[Ēostre|Ēostur]] month”<br/>
| April
|- style="vertical-align:top;"
|style="text-align:center;"|  5
| [[Þrimilcemōnaþ|Ðrimilce-mōnaþ]] || “Three-milkings month” &nbsp; &nbsp;<br/>
| May
|- style="vertical-align:top;"
|style="text-align:center;"|  6
| [[Ǣrra-Līða|Ærra-Liþa]] || “Ere-[[Litha]]”<br/>
| June
|- style="vertical-align:top;"
|style="text-align:center;"|  7
| [[Ǣrra-Līða#Æftera Līða|Æftera-Liþa]] || “After-[[Litha]]”<br/>
| July
|- style="vertical-align:top;"
|style="text-align:center;"|  8
| [[Weōdmōnaþ|Weōd-mōnaþ]] || “Weed month”<br/>
| August
|- style="vertical-align:top;"
|style="text-align:center;"|  9
| [[Hāliġmōnaþ|Hāliġ-mōnaþ]] {{small|or}}<br/>Hærfest-mōnaþ
| “Holy month” {{small|or}}<br/> “Harvest month”<br/>
| September
|- style="vertical-align:top;"
|style="text-align:center;"| 10
| [[Winterfylleth|Winter-fylleþ]] || “Winter-filleth”<br/>
| October
|- style="vertical-align:top;"
|style="text-align:center;"| 11
| [[Blōtmōnaþ|Blōt-mōnaþ]] || “[[Blót]] month”<br/>
| November
|- style="vertical-align:top;"
|style="text-align:center;"| 12
| [[Ġēolamonaþ|Ærra-ġēola mōnaþ]] || “Ere-[[Yule]]”<br/>
| December
|}
When an [[Intercalation (timekeeping)|intercalary]] month was needed, a third ''Litha'' month was inserted in mid-summer.{{sfnp|Newton|2000}}
===Old Celtic calendar===
The [[Coligny calendar]] (Gaulish/Celtic) is an Iron Age Metonic lunisolar calendar, with 12&nbsp;lunar months of either 29 or 30&nbsp;days. The lunar month is calculated to a precision of within 24&nbsp;hours of the lunar phase, achieved by a particular arrangement of months, and the month of EQUOS having a variable length of 29 or 30&nbsp;days to adjust for any lunar slippage.  This setup means the calendar could stay precisely aligned to its lunar phase indefinitely.
The lunar month is divided into two halves, the first of 15&nbsp;days and the second of 14 or 15&nbsp;days. The month is calculated to start at the first quarter moon, with the full moon at the centre of the first half-month and the dark moon at the centre of the second half-month.  The calendar does not rely on unreliable visual sightings.
An intercalary lunar month is inserted before every 30&nbsp;lunar months to keep in sync with the solar year. Every 276&nbsp;years this adds one day to the solar point, so if for example the calendar was 1,000&nbsp;years old, it would only have slipped by less than 4&nbsp;days against the solar year.
{| class="wikitable" style="text-align: center"
|-
! scope="col" |  !! scope="col" | Name
! width=60px | Days !! scope="col" | Meaning
! width=150px| Modern months
|-
| {{math|I}}-1 || Unknown || 30 ||  || Intercalary One
|-
| 1 || {{lang|xtg|Samonios}} || 30 || summer month || May-June
|-
| 2 || {{lang|xtg|Dumannios}} || 29 ||  || June-July
|-
| 3 || {{lang|xtg|Rivros}} || 30 || fat month  || July-August
|-
| 4 || {{lang|xtg|Anagantios}} || 29 || || August-September
|-
| 5 || {{lang|xtg|Ogronios}} || 30 || cold month || September-October
|-
| 6 || {{lang|xtg|Cutios}}    || 30 || wind month || October-November
|-
| {{math|I}}-2 || {{lang|xtg|[.]antaran[...]}}|| 30 ||  || Intercalary Two
|-
| 7 || {{lang|xtg|Giamonios}} || 29 || winter month || November-December
|-
| 8 || {{lang|xtg|Simivisonnios}} || 30 ||  || December-January
|-
| 9 || {{lang|xtg|Equos}}   || 29 or 30 || || January-February
|-
| 10 || {{lang|xtg|Elembivios}} || 29 ||  || February-March
|-
| 11 || {{lang|xtg|Edrinios}}  || 30 || month of heat || March-April
|-
| 12 || {{lang|xtg|Cantlos}} || 29 || month of song|| April-May
|-
|}
=== Old Hungarian calendar ===
'''Nagyszombati kalendárium''' (in Latin: ''Calendarium Tyrnaviense'') from 1579.
Historically Hungary used a 12-month calendar that appears to have been zodiacal in nature<ref>{{Cite web |last=Bodroghy |first=Gabor Z. |year=1998 |title=The Calendar by Marsigli: the ancient Hungarian Calendar |url=http://users.tpg.com.au/etr/rovas/marsigli.html |archive-url=https://web.archive.org/web/20070929091006/http://users.tpg.com.au/etr/rovas/marsigli.html |archive-date=29 September 2007 |access-date=8 August 2018 |website=The Ancient Hungarian Rovas}}</ref> but eventually came to correspond to the Gregorian months as shown below:<ref>{{Cite web |title=Hónapok nevei |url=http://www.freeweb.hu/magyarcsaladok/honapok_nevei.htm |archive-url=https://web.archive.org/web/20080227092508/http://www.freeweb.hu/magyarcsaladok/honapok_nevei.htm |archive-date=27 February 2008 |access-date=8 August 2018 |website=Free Web |language=hu}}</ref>
# Boldogasszony hava (January, 'month of the happy/blessed lady')
# Böjtelő hava (February, 'month of early fasting/Lent' or 'month before fasting/Lent')
# Böjtmás hava (March, 'second month of fasting/Lent')
# Szent György hava (April, 'Saint George's month')
# Pünkösd hava (May, 'Pentecost month')
# Szent Iván hava (June, 'Saint John [the Baptist]'s month')
# Szent Jakab hava (July, 'Saint James' month')
# Kisasszony hava (August, 'month of the [[Blessed Virgin|Virgin]]')
# Szent Mihály hava (September, 'Saint Michael's month')
# Mindszent hava (October, 'all saints' month')
# Szent András hava (November, 'Saint Andrew's month')
# Karácsony hava (December, 'month of Yule/Christmas')
=== Czech calendar ===
# Leden – derives from 'led' (ice)
# Únor – derives from 'nořit' (to dive, referring to the ice sinking into the water due to melting)
# Březen – derives from 'bříza' (birch)
# Duben – derives from 'dub' (oak)
# Květen – derives from 'květ' (flower)
# Červen – derives from 'červená' (red – for the color of apples and tomatoes)
# Červenec – is the second 'červen' (formerly known as 2nd červen)
# Srpen – derives from old Czech word 'sirpsti' (meaning to reflect, referring to the shine on the wheat)
# Září – means 'to shine'
# Říjen – derives from 'jelení říje', which refers to the [[estrous cycle]] of female elk
# Listopad – falling leaves
# Prosinec – derives from old Czech 'prosiněti', which means to shine through (refers to the sun light shining through the clouds)<ref>{{cite journal |last1=Kebrle |first1=Vojtěch |title=Česká jména měsíců, jejich význam a původ |journal=Naše řeč |date=1939 |volume=23 |issue=3 |pages=65–67 |url=http://nase-rec.ujc.cas.cz/archiv.php?lang=en&art=3372 |language=Czech |access-date=5 May 2021}}</ref>
=== Old Egyptian calendar ===
{{main|Egyptian calendar}}
The ancient civil Egyptian calendar had a year that was 365 days long and was divided into 12 months of 30 days each, plus 5 extra days (epagomenes) at the end of the year.<ref>{{Cite book |last=Clagett |first=Marshall |url=https://books.google.com/books?id=xKKPUpDOTKAC |title=Ancient Egyptian Science: A Source Book |date=1995 |publisher=American Philosophical Society |isbn=0-87169-214-7 |location=Philadelphia |page=28}}</ref> The months were divided into 3 "weeks" of ten days each. Because the ancient Egyptian year was almost a quarter of a day shorter than the solar year and stellar events "wandered" through the calendar, it is referred to as Annus Vagus or "Wandering Year".
#Thout
#Paopi
#Hathor
#Koiak
#Tooba
#Emshir
#Paremhat
#Paremoude
#Pashons
#Paoni
#Epip
#Mesori
=== Nisga'a calendar ===
The [[Nisga'a]] calendar coincides with the Gregorian calendar with each month referring to the type of harvesting that is done during the month.{{Citation needed|date=October 2008}}
#K'aliiyee = Going North – referring to the Sun returning to its usual place in the sky
#Buxwlaks = Needles Blowing About – February is usually a very windy month in the Nass River Valley
#Xsaak = To Eat Oolichans – Oolichans are harvested during this month
#Mmaal = Canoes – The river has defrosted, hence canoes are used once more
#Yansa'alt = Leaves are Blooming – Warm weather has arrived and leaves on the trees begin to bloom
#Miso'o = Sockeye – majority of Sockeye Salmon runs begin this month
#Maa'y = Berries – berry picking season
#Wii Hoon = Great Salmon – referring to the abundance of Salmon that are now running
#Genuugwwikw = Trail of the Marmot – Marmots, Ermines and animals as such are hunted
#Xlaaxw = To Eat Trout – trout are mostly eaten this time of year
#Gwilatkw = To Blanket – The earth is "blanketed" with snow
#Luut'aa = Sit In – the Sun "sits" in one spot for a period of time
=== French Republican calendar ===
{{main|French Republican calendar}}
This calendar was proposed during the French Revolution, and used by the French government for about twelve years from late 1793. There were twelve months of 30 days each, grouped into three ten-day weeks called ''décades''. The five or six extra days needed to approximate the tropical year were placed after the months at the end of each year. A period of four years ending on a leap day was to be called a ''Franciade''. It began at the autumn equinox:
* Autumn:
#[[Vendémiaire]]
#[[Brumaire]]
#[[Frimaire]]
* Winter:
#[[Nivôse]]
#[[Pluviôse]]
#[[Ventôse]]
* Spring:
#[[Germinal (French Republican Calendar)|Germinal]]
#[[Floréal]]
#[[Prairial]]
* Summer:
#[[Messidor]]
#[[Thermidor]]
#[[Fructidor]]
=== Eastern Ojibwe calendar ===
[[Ojibwe]] month names{{efn|name=Ojibwe-vowels|Due to Eastern Ojibwe is a [[vowel]] [[Syncope (phonology)|syncope]] dialect, the elided vowels (and the occasionally elided consonants) have been added back in the table below, shown in brackets.}} are based on the key feature of the month. Consequently, months between various regions have different names based on the key feature of each month in their particular region. In the Eastern Ojibwe, this can be seen in when the [[Catostomidae|sucker]] makes its run, which allows the Ojibwe to fish for them. Additionally, Rhodes<ref name=Rhodes->{{cite book |editor-first=Richard A. |year=1993 |orig-year=1985 |editor-last=Rhodes |title=Eastern Ojibwa-Chippewa-Ottawa Dictionary |series=Trends in Linguistics |publisher=Walter de Gruyter |place=Berlin, DE; New York, NY|isbn=978-3110137491}}</ref> also informs of not only the variability in the month names, but how in Eastern Ojibwe these names were originally applied to the [[lunar month]]s the Ojibwe originally used, which was a [[lunisolar calendar]], fixed by the date of ''Akiinaaniwan'' (typically December&nbsp;27) that marks when sunrise is the latest in the Northern Hemisphere.
:{| class="wikitable"
|- style="vertical-align:bottom;"
!Roman<br/>Month
!Month in<br/>Eastern&nbsp;Ojibwe{{efn|name=Ojibwe-vowels}}
!English<br/>translation
!Original order in the Ojibwa year
!Starting at the first full moon after:
|-
|rowspan=2|January<br><small>in those places that have a [[Catostomidae|sucker]] run during that time</small>
|''n[a]mebin-giizis''
|rowspan=2|[[Catostomidae|sucker]] moon
|rowspan=2|{{center|1}}
|rowspan=2|''Akiinaaniwan'' on 27 December
|-
|''n[a]meb[i]ni-giizis''
|-
|February
|''[o]naab[a]ni-giizis''
|Crust-on-the-snow moon
|{{center|2}}
|25 January
|-
|March
|''zii[n]z[i]baak[wa]doke-giizis''
|Sugaring moon
|{{center|3}}
|26 February
|-
|rowspan=2|April<br><small>in those places that have a [[Catostomidae|sucker]] run during that time</small>
|''n[a]mebin-giizis''
|rowspan=2|[[Catostomidae|sucker]] moon
|rowspan=4|{{center|4}}
|rowspan=4|25 March
|-
|''n[a]meb[i]ni-giizis''
|-
|April<br><small>in those places that do not have a [[Catostomidae|sucker]] run during that time</small>
|rowspan=2|''waawaas[a]gone-giizis''
|rowspan=2|Flower moon
|-
|May<br><small>in those places that have an April [[Catostomidae|sucker]] run</small>
|-
|May<br><small>in those places that have a January [[Catostomidae|sucker]] run</small>
|rowspan=2|''g[i]tige-giizis''
|rowspan=2|Planting moon
|rowspan=2|{{center|5}}
|rowspan=2|24 April
|-
|June<br><small>in those places that have an April [[Catostomidae|sucker]] run</small>
|-
|June<br><small>in those places that have a January [[Catostomidae|sucker]] run</small>
|''[o]deh[i]min-giizis''
|Strawberry moon
|{{center|6}}
|23 May
|-
|July
|''miin-giizis''
|Blueberry moon
|{{center|7}}
|22 June
|-
|August
|''[o]dat[a]gaag[o]min-giizis''
|Blackberry moon
|{{center|8}}
|20 July
|-
|September
|''m[an]daamin-giizis''
|Corn moon
|{{center|9}}
|18 August
|-
|rowspan=2|October
|''b[i]naakwe-giizis''
|Leaves-fall moon
|rowspan=2|{{center|10}}
|rowspan=2|17 September
|-
|''b[i]naakwii-giizis''
|Harvest moon
|-
|November
|''g[a]shkadin-giizis''
|Freeze-up moon
|{{center|11}}
|16 October
|-
|December
|''g[i]chi-b[i]boon-giizis''
|Big-winter moon
|{{center|12}}
|15 November
|-
|January<br><small>in those places that do not have a [[Catostomidae|sucker]] run during that time</small>
|''[o]shki-b[i]boon-gii[zi]soons''
|Little new-winter moon
|{{center|13<br/>{{small|(leap month)}}}}
|{{small|only used if the new moon after ''g[i]chi-b[i]boon-giizis'' occurs before ''Akiinaaniwan'' on 27 December.}}
|}
== See also ==
{{wiktionary}}
* [[Assyrian calendar]]
* [[Chinese calendar]]
* [[Egyptian calendar]]
* [[Ethiopian calendar]]
* [[French Republican calendar]]
* [[Kurdish calendar]]
* [[Lunar month]]
* [[Maya calendar]]
* [[Month of year]]
== Footnotes ==
{{notelist}}
== References ==
{{reflist}}
==Sources==
{{refbegin|30em|indent=yes}}
*{{cite journal |last=Kapoor |first=Ramesh|date=2021
|title=Fixing the chronology in Tai-Ahom chronicles by using astronomical references
|journal=Journal of Astronomical History and Heritage|doi=10.3724/SP.J.1440-2807.2021.03.07   |volume=24 |issue=3 |pages=665–687 |url=https://www.researchgate.net/publication/354689630 }}
*{{cite book |last=Phukan Baruah|first=B. N.N.|date=1964|title= Ahom lexicon |publisher=The government of Assam in the department of historical and antiquarian studies |url=https://books.google.com/books?id=MfqkboCUdzwC}}
* {{cite web |last=Newton |first=Dr Sam |year=2000 |title=The Old English Calendar |website=Wuffings |url=http://www.wuffings.co.uk/OECalendar.htm |access-date=8 August 2018}}
* {{Cite book |last=Esslemont |first=J. E. |url=http://reference.bahai.org/en/t/je/BNE/ |title=Bahá'u'lláh and the New Era |publisher=Baháʼí Publishing Trust |year=1980 |isbn=0-87743-160-4 |edition=5th |location=Wilmette, Illinois, USA }}
{{refend}}
{{Time topics}}
{{Time measurement and standards}}
{{The Moon}}
{{Authority control}}
[[Category:Months| ]]
[[Category:Calendars]]
[[Category:Orbit of the Moon]]
[[Category:Orders of magnitude (time)]]
[[Category:Units of time]]