Buddhist holidays and celebrations are often calculated according to the Lunar calendar, except in Japan, where the Solar calendar is used. In different Asian countries, the beginning of the year varies and leap years are calculated differently.
In South Asian Theravāda Buddhism, the New Year is celebrated according to the old solar calendar on April 15. It is a carnival-like water-splashing festival, where water is thrown on friends and passersby in the streets as a wish for good luck.