Krishna Janmashtami is the celebration of the birth of Lord Shri Krishna, the incarnation of Lord Vishnu, believed to have been born about five thousand years ago in Mathura in 'Dwapar Yuga'.

Krishna Janmashtami is observed on the eighth day of the dark half (Krishna Paksha) of the month of Shraavana in the Hindu calendar, when the Rohini Nakshatram is ascendent. The Hindu calendar being lunar, these two events [the day being the eighth of the waning moon (Krishna-paksha Ashtami) and the Rohini Nakshatram being ascendent] may overlap for only a few hours. In such an event, the festival may be celebrated on different (but successive) days by different people, depending on their local or family traditions.