TheThai lunar calendar (Thai:ปฏิทินจันทรคติ,RTGS: patithin chanthrakhati,pronounced[pà.tì.tʰīnt͡ɕān.tʰrá(ʔ).kʰā.tìʔ], literally,Specific days according to lunar norms), orTai calendar, is alunisolarBuddhist calendar. It is used for calculating lunar-regulated holy days. Based on theSuriyaYatra,^{[clarification needed]} with likely influence from the traditional HinduSurya Siddhanta, it has its own unique structure that does not require the Surya Siddhanta to calculate. Lunisolar calendars combinelunar andsolar calendars for a nominalyear of 12months. An extra day or an extra 30-day month isintercalated at irregular intervals.

TheThai solar calendar (Thai:ปฏิทินสุริยคติ,RTGS: patithin suriyakhati,[pà.tì.tʰinsù.rí.já.kʰàʔ.tìʔ]), Thailand's version of theGregorian calendar, replaced thepatithin chanthrakhati inAD 1888 / 2431BE forlegal andcommercial purposes. In both calendars, the four principallunar phases determineBuddhistUposathas, obligatory holy days for observant Buddhists. Significant days also include feast days.

Note that the Thai and the Chinese lunar calendars do not directly correspond.Thai Chinese likewise observe their Uposatha andtraditional Chinese holidays according tosolar terms, two of which correspond to one lunar phase. These also move with respect to the solar calendar, and so it is common for Thai calendars to incorporate both Thai andChinese lunar calendar-based events.

Mundane astrology also figures prominently inThai culture, so modern Thai birth certificates include lunar calendar dates and the appropriate Thai Zodiacal animal year-name for ThaiHora (Thai:โหราศาสตร์,RTGS: horasat). The Thai Zodiac is similar to the Chinese, though theDragon is replaced by the Naga (งูใหญ่), and in Northern Thailand thePig is occasionally replaced with an Elephant.

To keep the years in sync with the seasons, Thai lunar years may add a day to the 7th month or repeat the 8th month. Therefore, years may have one of three lengths – 354, 355 or 384 days – yet retain anominal length of twelve months.

• The 354-day-long years consist of 12 "normal months", and such a year is called a "normal-month year" (Thai:(ปี) ปกติมาส,RTGS: (pi) pakatimat,[(pī)pà.kà.ti.mâːt]).
• The 355-day-long yearsadd an extra day to the normally 29-day-long 7th month; such a year is called an "extra-day year" (Thai:(ปี) อธิกวาร,RTGS: (pi) athikawan,Thai pronunciation:[(pīː)ʔà.tʰí.kà.waːn]).

• The 384-day-long years repeat the 30-day-long 8th month, thus keeping the month count at 12. Nevertheless, a year of 384 days is called an "extra-month year" (Thai:(ปี) อธิกมาส,RTGS: (pi) athikamat,[(pīː)ʔà.tʰí.kà.mâːt]).

The Thai lunar calendar does not mark the beginning of a new year when it starts a new 1-to-12 count, which occurs most frequently in December.

The Thai solar calendar determines aperson'slegal age and the dates ofsecularholidays, including the civilnew year and the three days of thetraditional Thai New Year, which begin the next Twelve-year animal cycle. Should the holidays fall on aweekend, it also accommodates these as well as some of the principal lunar festivals with a compensatory day off (Thai:วันชดเชย,RTGS: wan chotchoei).

13 April of the solar calendar occasions the beginning of the traditionalThai New Year (Songkran) and is the day that a year assumes the name of the next animal in the twelve-year animal cycle;^[1] Thai Chinese communities may observe the name-change earlier in accordance with theChinese New Year.

The Thai names of the months were borrowed from Khmer, which were in turn borrowed from Archaic Vietnamese.^[2]

In the modern Thai calendar, months (Thai:เดือน,RTGS: duean,[dɯ̄ːan], meaning "month" or "Lunation") are defined by lunar cycles. Successive months (or lunations) are numbered from 1 to 12 within the Thai year. As in otherBuddhist calendars, these months have names that derive fromSanskrit, but for the most part are only known by Thai astrologers.^[3]

Two successive lunations take slightly more than 59 days. The Thai lunar calendar approximates this interval with "normal-month" pairs (ปกติมาส,RTGS: pakatimat) that are alternately 29 and 30 days long. 29-day "hollow months" (เดือนขาด,RTGS: duean khat,[dɯ̄ːankʰàːt]) are odd-numbered (เดือนคี่,RTGS: duean khi,[dɯːan.kʰî]); 30-day "full months" (เดือนถ้วน,RTGS: duean thuan,[dɯ̄ːantʰûan]) are even-numbered (เดือนคู่,RTGS: duean khu,[dɯ̄ːankʰûː]).

To keep the beginning of the month in sync with the new moon, from time to time either the normally "hollow" Month 7 takes an extra day, or an extra "full" Month 8 follows a normal "full" Month 8.

Months 1 and 2 are named inarchaicalternate numbers, with the remainder being named in modern numbers.^[4]

Month 1, "duean ai" (เดือนอ้าย,[dɯ̄ːanʔâːj]), begins the cycle of counting the months anew, most frequently in December, but does not signify the beginning of a new year.^[5]Ai, anarchaic word in Thai but not in other dialects, meansfirst.^[6] An odd-numbered hollow month, it is 29 days long.

Month 2, "duean yi", (เดือนยี่,[dɯ̄anjîː], from archaic ญี่ meaning2)^[6] is an even-numbered full month.

Months 3–6, "duean 3–6", use the modern reading ofThai numerals, as do all remaining months. Months 3–6, alternate between 29-day hollow months and 30-day full months.

Month 7, "duean 7", a hollow month is normally 29 days long in years of 354 days, but adds an extra day (อธิกวารRTGS: athikawan) when required for 355-day-long years (ปีอธิกวาร,RTGS: pi athikawan).

The eighth month, "duean 8", is a 30-day full month.

Athikamat (อธิกมาส,Thai pronunciation:[ʔà.tʰí.kà.mâːt])) is the extra month needed for a 384-day-longpi athikamat (extra-month year;ปีอธิกมาส,Thai pronunciation:[pī.ʔà.tʰí.kà.mâːt]). Month 8 repeats as เดือน ๘/๘ or Month 8/8, variously read as "duean paet thab paet" (เดือนแปดทับแปด) or "duean paet lang" (เดือนแปดหลัง)

Months 9–12, "duean 9–12", complete the lunar cycle.

Months divide into two periods designated by whether they arewaxing or waning:

• Waxing :khang khuen (ข้างขึ้น), the period from new moon to full moon, is always 15 days long.
• Waning :khang raem (ข้างแรม), the period from full moon to new moon, which is 14 days long in hollow months, except when Month 7 adds an extra day, and 15 days long in full months.

Aweek is calledSapda/Sappada (Thai:สัปดาห์,[sàp.dāː,sàp.pà.dāː]). The term is defined by theRoyal Institute Dictionary (RID) as a 7-day period beginning on Sunday and ending Saturday.^[7] When referring to lunations, however, it is the 7-, 8- or (rarely) 9-day interval betweenquartilelunar phases; that is, from onewan phra (วันพระ) to the next.

Whilesolar-calendar weekdays have names, lunar-calendar days number sequentially from 1 to 14 or 15 in two segments depending on whether the moon is waxing or waning. For example, "raem 15 kham duean 12แรม ๑๕ ค่ำ เดือน ๑๒" means "Waning of the 15th Night of the 12th Lunar Month".

Khamค่ำ, evening, is considered to be the evening of the common day that begins and ends at midnight, rather than of a day that begins and ends at dusk. Past practice may have been different.

• Wan Phraวันพระ, Buddhist holy days
  • Wan Thamma Sawanaวันธรรมสวนะ BuddhistUposatha regularly fall on:
    • Khuen 8ขึ้น ๘ first-quarter moon
    • Khuen 15ขึ้น ๑๕ full moon; also calledwan phenวันเพ็ญ day [of] full [moon]. However,Wan Deuan Phenวันเดือนเพ็ญ, the actual day of thefull moon and khuen 15 kham do not always fall on the same day.
    • Raem 8แรม ๘ third-quarter moon
    • Raem 14 (15)แรม ๑๔ (๑๕) the last day of the lunar month; also calledwan dapวันดับ day [moon is] quenched, [or goes] out.
• Wan wai phra chanวันไหว้พระจันทร์, called "Day [of] Respect [for] the Holy Moon", is the actual day theHarvest moon becomes full. It occurs onkhuen 14 (15) kham duean 10ขึ้น ๑๔ (๑๕) ค่ำ เดือน ๑๐ (Waxing 14 (15) Evening, Month 10.)

Uposatha, colloquially calledวันพระ, are the New, First-quarter, Full, and Third-quarter Moon-days. These are not normally days off (วันหยุด), except forbutcher,barber, andbeautician shops that observe theEight Precepts. Annual holidays and seasonal festivals collectively are calledวันนักขัตฤกษ์.

Festivals orfairs are calledเทศกาล; these may be further styled asประเพณี "traditional" and asThai:พิธี, "rite" or "ceremony". The table shows theprincipal ones governed by the moon in yellow.

Work holidays prescribed by the government are calledThai:วันหยุดราชการ; those regulated by the moon are red.

Weekends are normally days off; if a holiday normally observed by a day off falls on a weekend, the following Monday is a compensatory day offThai:วันชดเชย.

Notes:

† The Chinese New Year uses different methods of determining intercalary months, so this festival sometimes occurs a month earlier or later.

‡ Month 8/8 in years with the extra month.

Thai orthography spells most native words phonetically, though there is no definitive system fortranscription into Roman letters. Here, native Thai words are immediately followed by a vocabulary entry in this pattern:

Phonetic Thai (Thai phonetic respelling, if different) [Comment] definition; variant definitions.

Example:

Thai ไทย (ไท) [Archaic] free, frank; Thai race, language,alphabet;citizen of Thailand.

Sanskrit loan words follow different rules [the way English grammatical rules vary for words of Greek and Latin origin ('ph-' in 'phonetic' being pronounced /f/, for example.)] Entered below in order of first appearance, these vocabulary entries are in this pattern:

Sanskrit สันสกฤต (สันสะกฺริด /san-sa-krit/)

Literally means "well done", "polished","cultured" or "perfected" in a modern usage (which implies the language of cultured persons); Sanskrit alphabet,language, writing; [presumed] compound of

• san สัน (-/son/) derived from the prefix "saṃ" meaning "together, with, completely"
• skrit สกฤต (สะกฺริต /sa-krit/) derived from the root "kr" meaning "do or make".

Chanthrakhati จันทรคติ (จันทฺระคะติ)

"Lunar norms", Lunar Calendar; compound of

• Chanthra- จันทร- (จันทฺระ) :Chan จันทร์ (จัน) moon, lunar +
• Kati คติ (คะติ) : ways, principles, norms

Patithin ปฏิทิน (ปะติทิน)

Calendar; compound of

• Pati- ปฏิ- (ปะติ-) : anti-, re-, for, specific +
• -thin (-ทิน) : [from Sanskritdina] : day.
• patithin means for days, specific days or fixed days

Patitin Chanthakhati ปฏิทินจันทรคติ (ปะติทินจันทระคะติ)

"Specific days according to lunar norms", Lunar Calendar

Suriyakhati สุริยคติ (สุริยะคะติ)

Solar norms, Solar Calendar; compound of

• Suriya สุริย or สุริยะ :Athit อาทิตย์, the sun, Sol +
• Khati คติ (คะติ) : ways, principles, norms

Prokkatimat ปรกติมาส (ปฺรกกะติมาด)

normal month; compound of

• Prokkati ปรกติ (ปฺรกกะติ) :pakati ปกติ (ปะกะติ) ordinary, usual, normal +
• Mat มาส (มาด) :duean (เดือน) month.

Athikamat อธิกมาส (อะทิกะมาด)

month added in leap-month lunar years

Athikawan อธิกวาร (อะทิกะวาน)

day added in leap-day lunar years; compound of

• Athika (Sanskrit:adhika) : additional +
• -wan วาร (Sanskrit:vāra) :wan วัน day.

Athikasurathin อธิกสุรทิน (อะทิกะสุระทิน)

day added to February in a solar leap year.

EnglishWikisource has original text related to this article:

Proclamation on Observance of New Year's Day on 1 January, dated 24 December 1940

• Public holidays in Thailand
• The Royal Institute of Thailand
• Thai solar calendar
• Thai 6-hour clock
• Time in Thailand
• Traditional Burmese calendar

• Diller, Anthony; Preecha Juntanamalaga (December 1995)."Thai Time".International Conference on Tai Languages and Cultures, Thammasat University. Australian National University. Archived fromthe original on 2002-12-10. Retrieved22 June 2008.
• Eade, J.C.The calendrical systems of mainland south-east Asia.ISBN 90-04-10437-2 (Cited by Diller & Preecha)
• Sethaputra, So.New Model English - Thai Dictionary,ISBN 974-08-3253-9

• Thai Time by Anthony DillerArchived 2008-08-20 at theWayback Machine – last changed 10 January 2002.
• How Chula Sakarat Dates Work^[usurped] in Thailand: article for stamp collectors recovered 20 December 2007.
• Thai Lunar Calendar (BE.2300-2584) (Thai Language)

• Time in Thailand
• Lunisolar calendars
• Specific calendars
• Culture of Thailand
• Observances set by the Thai lunar calendar

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