Asalha Puja is celebrated on the eighth lunar month during a full moon day. Asalha, according to the ancient Indian calendar, is the month when monsoon begins. During this time of the year Buddha and his followers would put their traveling on hold. The monasteries of the present day still continue with the tradition. There is a three month long retreat. This retreat starts from the Dhamma day and continues till the Pavarana day. The ordination for the short-term monks also takes place on this day. This ordination is for those people who cannot renounce their present life yet are interested in the principles of Buddhism.

Asalha Puja is one of the important festivals of Theravada Buddhists as it celebrates the first teaching of Gautama Buddha. According to legends Buddha achieved enlightenment but was not interested to preach. However, on Brahma Sahampati`s insistence Buddha agreed to preach and he delivered his first sermon in Varanasi. At the end of his sermons one of his friends urged Buddha to accept him as his disciple. Buddha complied and it was done by a simple ceremony. Buddha`s band of followers kept on going and thus the order of the monks was formed.

The teachings of the Buddha consist of four noble truths. This doctrine forms the basis of all Buddhist schools. Another significance is attached to the Asalha Puja Day. This was also the day when Rahula was born.