तिरुवोणम (ओणम)

अन्य वर्तनी: Onam, Thiruvonam, Thiru onam, Kerala harvest।

केरल का फसल उत्सव, जो राजा महाबली के वार्षिक आगमन का प्रतीक है। तिरुवोणम दस दिवसीय पर्व का दसवाँ और प्रमुख दिन है।

Onam is dated in the Malayalam solar calendar, not the lunar one: it is the day the nakshatra Thiruvonam — Shravana — runs while the Sun is in Simha, the month Malayalis call Chingam. Chingam runs about 31 days and a nakshatra returns every 27, so occasionally two Thiruvonams fall inside the month; the later one is kept, because the ten days of Onam count backwards from it to Atham and that run has to fit inside Chingam too.

• Verified against observed Onam dates 2020-2025; 2024 is the only year in that span with two Thiruvonams in Chingam, and Kerala kept the later one (15 September).
• The nakshatra is taken as the one running at sunrise.