The most important month in the Tibetan lunar calendar is Saga Dawa, the 4th month and the 15th day of the lunar month. Düchen means “Great Occasion” and this day is the single most holy day of the year for Tibetan Buddhists. Saga Dawa Düchen commemorates the Birth, Enlightenment, and Parinirvana of Buddha Shakyamuni marked on the same day of the Full Moon within this month. 

Although, there is a specific separate day in which Buddha Shakyamuni’s birth is celebrated. This is referred to as Tampei Düchen, this year falling on Monday 2nd June.