Onam is the state festival of Kerala and it is celebrated with extreme enthusiasm and zeal throughout the state irrespective of caste, creed and community. It is celebrated in order to welcome the spirit of King Mahabali who is said to visit the place at the time of Onam. The festival is marked with wonderful celebrations including intricate rituals, grand feast, songs, dance, games and fairs. It is also known as the harvest festival of the state and is celebrated in the beginning of the first month of Malayalam Calendar (Kolla Varsham) called ‘Chingam’. This month falls in August-September according to the Gregorian calendar and in Bhadrapada or Bhadon according to the Indian (Hindu) Calendar.

When Is Onam Celebrated
Onam is celebrated over ten days; it comes to an end with the grand celebrations on the tenth day called ‘Thiruvonam’. Onam celebrations start from the day of Atham and culminate on Thiruvonam. At some places the celebrations even extend to twelve days called as ‘Chatayam’. However, Atham and Thiru Onam are the most important days for Onam celebrations. The days for these celebrations are decided according to the position of stars. The festival is supposed to start from the appearance of the lunar asterism (a cluster of stars smaller than a constellation) Atham (Hastha), that appears ten days before asterism Thiruvonam. Thiruvonam actually corresponds to the Shravan day in the month of August or September and that is why it is also known as Sravanotsavam. At this time, the sun is also located in the Zodiac sign of Leo which in return happens to be located in the sun’s house as well.

Significance of Onam Day
Onam is celebrated in order to honor King Mahabali, one of the most respected kings of the state. The entire festival is celebrated in order to welcome his spirit to the place as he is supposed to visit the state during this period. It is believed that that it was on the this day in the month of Chingam when Lord Vishnu took in avatar of Vaamana, came to the state of King Mahabali and sent him to nether world. It is said that since that day the festival of Onam is celebrated in order to memorize his wonderful reign of peace and prosperity in the kingdom. In order to welcome their respected ruler, people lay flower mats (Pookalam) in the front courtyard, arrange grand feast (Onasadya), dance, play, and celebrate. All this is done to make the King feel that his people are still happy and prosperous. It is believed that Onam celebrations started during the Sangam period as some evidences of the celebrations related to the Kulasekhara Perumals (800 AD) have been found. It is said that during that time Onam was celebrated for a month.