Onam Date

Onam follows Thiruvonam in the Malayalam month of Chingam, following the Shravana nakshatra. It runs for about 10 days in the regions where it is observed.

A common question is why the date moves. The Hindu calendar is lunisolar: it tracks the moon for months and the sun for years, which means the civil date of a lunar festival drifts by up to about a fortnight from one year to the next. Islamic festivals follow the purely lunar Hijri calendar and move roughly eleven days earlier every year, subject to moon sighting. A handful of festivals — Makar Sankranti, Vaisakhi, Pongal and the other solar ones — stay on nearly the same date. The entry below tells you which of these applies here.