2029
Wednesday, 19 September 2029
In 2029 the nakshatra runs from 10:40 am on 18 Sep to 11:47 am on 19 Sep; it is running at sunrise (the usual rule, called udaya tithi) on Wednesday, 19 September 2029, so that is the day of Onam.
2030
Monday, 9 September 2030
In 2030 the nakshatra runs from 7:57 pm on 8 Sep to 7:00 pm on 9 Sep; it is running at sunrise (the usual rule, called udaya tithi) on Monday, 9 September 2030, so that is the day of Onam.
How the date is fixed
Onam is the day in the bright half of Bhadrapada on which the Moon is in Shravana nakshatra at sunrise.
About
Onam is fixed by nakshatra, not tithi: the main day, Thiruvonam, is the day on which the Moon is in Shravana (Thiruvonam) nakshatra during the Malayalam solar month of Chingam (Simha), in August or September. In lunar terms this is almost always Bhadrapada Shukla, since the Bhadrapada full moon falls near Purva Bhadrapada and Shravana comes three nakshatras earlier. The ten days from Atham (Hasta) to Thiruvonam are the festival; the nakshatra at sunrise is taken, and the Kerala government publishes the dates by its own almanac. The festival recalls the annual return of King Mahabali to his people.
How it is observed
Flower carpets (pookalam) for ten days, the Onam sadya feast on Thiruvonam, boat races and Kathakali.