Thai calendar

In Thailand, two main calendar systems are used alongside each other: the Thai solar calendar, based on the Gregorian calendar and used for official and most day-to-day purposes, and the Thai lunar calendar (a version of the Buddhist calendar, technically a lunisolar calendar), used for traditional events and Buddhist religious practices.

The use of the solar calendar was introduced in 1889 by King Chulalongkorn (Rama V), replacing the lunar calendar in official contexts. The beginning of the year was originally marked as April 1st, however this was changed to January 1st in 1941. The days and months now correspond exactly to the Gregorian calendar. The years follow the Buddhist Era, introduced in 1913 to replace the Rattanakosin Era, which in turn replaced the Chula Sakarat in 1889. The reckoning of the Buddhist Era in Thailand is 543 years ahead of the Gregorian calendar (Anno Domini), so the year 2024 AD corresponds to B.E. 2567.

The lunar calendar contains 12 or 13 months in a year, with 15 waxing moon and 14 or 15 waning moon days in a month, amounting to years of 354, 355 or 384 days. The years are usually noted by the animal of the Chinese zodiac, although there are several dates used to count the New Year.

As with the rest of the world, the seven-day week is used alongside both calendars. The solar calendar now governs most aspects of life in Thailand, and while official state documents invariably follow the Buddhist Era, the Common Era is also used by the private sector. The lunar calendar determines the dates of Buddhist holidays, traditional festivals and astrological practices, and the lunar date is still recorded on birth certificates and printed in most daily newspapers.