Vaisakhi, 13 April

Vaisakhi falls in mid April, and the date varies between thirteen and fourteen April depending on the year, a variation with a specific and fairly recent cause. The festival's religious significance for Sikhs rests on the founding of the Khalsa by Guru Gobind Singh at Anandpur Sahib in 1699, the occasion on which the first five baptized members, the Panj Pyare, were initiated, layered onto an older Punjabi harvest festival that predates Sikhism and continues to be marked as a harvest occasion by the wider regional population as well.

The date's instability traces to a genuine and unresolved dispute over the calendar Sikhs should use to fix it. In 2003 the Shiromani Gurdwara Parbandhak Committee adopted the Nanakshahi calendar, a fixed solar calendar designed by Pal Singh Purewal that sets Vaisakhi permanently on April 14, intended to correct the older Bikrami calendar's tendency to drift against the Gregorian year. Several traditionalist bodies, including Damdami Taksal and the Sant Samaj, rejected the reform and continue to calculate Vaisakhi by the older Bikrami calendar, whose Gregorian equivalent varies year to year between April 13 and April 14, which is the direct source of that variation.