The most important festivals of Assam are the Bihus, celebrated with joy and abundance by all Assamese people irrespective of caste, creed, religion, faith and belief. In a year there are three Bihu festivals known as Rongali, bhogali and Kangali. The most important and colourful of the three Bihu festival is the Spring festival "Bohag Bihu" or Rangali Bihu celebrated in the middle of April. This also initiates the agricultural season. The merriments include dances accompanied on the wild and lusty beats of Dhol and Pepa (buffalo hornpipe). Songs sung in this Bihu are woven around themes of love and often carry erotic overtones. People adorn traditional attires like Dhoti, Gamocha and Chadar, Mekhala.
Bihu dances performed by young boys and girls characterised by brisk stepping, flinging and flipping of hands and swaying of hips represents youthful passion, reproductive urge and 'Joie-de-vivre'.
Magh or the Bhogali Bihu, the harvesting festival is celebrated in January by community feast, buffalo fight and such other entertainment, compared to "Rongali" and Bhogali Bihu, "Kati Bihu" is a tame affair celebrated in the month of Kartika. Tribal groups like the Misings the Deoris and the Morans celebrate "Bihu" with dances of their own distinctive style. In more recent time Assam saw a fairly large scale migration of people from other parts of India, the Santhals, Gonds, Mundas and others from Bihar, Orissa and Madhya Pradesh, brought as indentured laboures for tea gardens also carried with them distinct cultural heritage which blossomed forth in exotic festivals like Tusu Puja, Sarak Puja, Karam Puja and captivating dance like Jhumur.
Baishagu Famous for its myriad of colours and merriment, 'Baishagu' is generally celebrated by the Boro kacharis in the month of baishak or mid April. It is the most cherished festival of the Boros, as the Spring celebration at the advent of the new year. The first day begins with the cow-worship. The next day which synchronizes with the first day of month of 'Bohag' of the Assamese almanac, the actual marriment begins with the young people of each household reverentially bowing down to their parents and elders. The supreme deity 'Bathou' or Lord Shiva is also worshipped on this day by offering him chicken and rice beer. In the Baishagu dance there is no bar of either of age or sex to join in their respective groups. The traditional musical instruments that are used in this danc festival are 'Kham' (drum), 'Jotha' (Manjari), 'Khawbang' (Taal), 'Gogona' (mouth-organ) and 'Siphung' (Flute) etc. It is also customary at the close of Baishagu festival to offer community prayer at a particular place called, 'Garjasali'.
Ali-Ai-Ligang This again is a spring festival celebrated by the Mising tribe. This is one of the most colourful festivals of Assam. It is organised in the month of 'Ginmur Polo' (February-March) on the first Wednesday of the month. 'Ali' means root, 'Ai' means fruit and 'Ligang' means sow. Hence, it is festival which initiates cultivation. Fish is essential in the feast and certain taboos like cutting trees, fishing, ploughing, burning jungles are strictly observed. Young boys and girls perform this dance.