Onam is celebrated in the beginning of the month of Chingam, the first month of Malayalam Calendar (Kollavarsham). There are actually four days of Onam. The most important day of Onam (known as Thiru Onam) is the second day. Festivities actually commence around 10 days before this day (on Atham), with the preparation of floral arrangements (pookalam) on the ground in front of homes.
- In 2014, Thiru Onam is on September 7. (Atham is on August 29).
- In 2015, Thiru Onam is on August 28. (Atham is on August 18).
- In 2016, Thiru Onam is on September 14.
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