The Concise Oxford Dictionary of World Religions (489 page)

darapada; A
vin
,
vayuja; M
rga
r
a, Pau
a; M
gha, Ph
lguna. Every two or three years a thirteenth month was added to adjust the lunar year to the solar year.

Buddhism
The spread of Buddhism did not take with it a calendar which it then imposed on other countries; rather, it adapted to local calendars, and worked its own
festivals
into the local scene. Buddhist calendars thus vary from culture to culture.
Sikhism
The Sikhs' religious calendar is a modified form of the Bikram
calendar. The year is solar (23 minutes 44 seconds shorter than the Christian year) and the months are lunar. Lunar month dates, varying within fifteen days, are used for
gurpurbs
. So in 1984 Gur
Gobind Si
gh's