On what day is Buddha's Birthday? That's simple. Just calculate the first full moon day of the sixth month of the Buddhist lunar calendar, which would be the fourth month of the Chinese calendar, except in years in which there's an extra full moon, and then Buddha's birthday falls in the seventh month. Well, except where it starts a week earlier. And in Tibet it's usually a month later. Oh, and in Japan, Buddha's Birthday always is April 8.
Or, you could follow the guide below. For more about how Buddha's birthday is celebrated, see "Buddha's Birthday."
Buddha's Birthday in Japan
In Japan, Buddha's birthday is called Hanamatsuri, or “Flower Festival." On this day people bring fresh flowers to temples in remembrance of the Buddha's birth in a grove of blossoming trees.
In Japan, Buddha's birthday is observed every year on April 8.
For more about Buddhism in Japan, see "Buddhism in Japan: A Brief History."
Buddha's Birthday in Korea
In South Korea, Buddha's birthday is a gala week-long celebration that ends on the first full moon day of the lunar month Vesakha, which usually falls in May. This full moon day is the most commonly observed date for Buddha's birthday. Here are upcoming dates for the celebration in South Korea:
2009: May 2-May 8
2010: May 15-May 21
2011: May 4-May 10
Throughout Korea, city streets and temples are decorated with lanterns. At Jogyesa Temple in Seoul, the first day begins with religious ceremonies, followed by a street fair near the temple. In the evening a gala lantern parade stretches for miles through the heart of Seoul.
Buddha's Birthday in Southeast Asia
Theravada is the dominant form of Buddhism in Sri Lanka, Thailand, Cambodia, Burma (Myanmar) and Laos. Theravadins combine observance of Buddha's birth, enlightenment and death into one holiday, called Vesak, Visakha, or Wesak, and sometimes Buddha Day.
Vesak Puja is the most holy day of the year for Theravada Buddhists, marked by visits to temples, candlelight processions and observance of Uposatha Precepts.
2009: May 8
2010: May 21
2011: May 10
For more about this holiday see "Vesak Puja."
Buddha's Birthday in Tibet
Saga Dawa is the entire fourth month of the Tibetan calendar, which usually begins in May and ends in June. The seventh day of Saga Dawa is the date of the historical Buddha's birth for Tibetans. However, the Buddha's birth, enlightenment and entry into Nirvana at his death are observed together on the 15th day of Saga Dawa, called Saga Dawa Duchen. This is the single most important holiday for Tibetan Buddhism, usually observed with pilgrimages and other visits to temples and shrines.
In 2009, Saga Dawa Duchen falls on June 7.
In 2010, Saga Dawa Duchen falls on May 27.
See also "Tibetan Buddhism: An Introduction."
Buddha's Birthday in China and Elsewhere
In most of China and most other parts of Asia, Buddha's Birthday coincides with the dates for Vesak Puja, in Southeast Asia (see above). However, most Mahayana Buddhists celebrate the day as Buddha's birthday alone, and observe the Buddha enlightenment and parinirvana on other days.