The exact date of Vesākha varies according to the lunar calendars used in different traditions. In Theravada countries following the Buddhist calendar, it falls on a full moon Uposatha day. This is typically in the 5th or 6th lunar month. Vesākha Day in China is on the eighth of the fourth month in the Chinese lunar calendar. The date varies from year to year in the Western Gregorian calendar. It usually falls in April or May. In leap years Vesākha is celebrated in June.