The Thai lunar calendar, or Tai calendar, is a lunisolar Buddhist calendar. It is used for calculating lunar-regulated holy days. Based on the SuriyaYatra, with likely influence from the traditional Hindu Surya Siddhanta, it has its own unique structure that does not require the Surya Siddhanta to calculate. Lunisolar calendars combine lunar and solar calendars for a nominal year of 12 months. An extra day or an extra 30-day month is intercalated at irregular intervals.

Loy Krathong is a Thai festival celebrated annually throughout Thailand and in nearby countries with significant South Western Tai cultures. The name could be translated as "to float ritual vessel or lamp," and comes from the tradition of making krathong or buoyant, decorated baskets, which are then floated on a river. Many Thais use the krathong to thank the Goddess of Water and River, Goddess Khongkha or to worship the Holy Buddha's hair pagoda in heaven in Buddhist beliefs. This festival traces its origin back to India.