Boun Khao Phansaa, which marks the beginning of “Buddhist Lent”, is celebrated yearly on July. A legend said that, there was once a group of six monks walking during the rainy season. They were careless about where they put their feet, stepping on frogs and crushing new rice plants. This angered the farmers who complained to the Buddha. The Buddha made the rule for the Sangha, the community of monks, to observe Khao Phansaa, which means “entering the rainy season.” The traditionally lay people are not allowed to get married until the end of the Buddist Lent which is less making parties during three months Khao Phansa. Many take time away from work to make merit for deceased relatives. They also offer robes to become novices or monks.
During this time devout people often abstain from alcohol. They pray for assistance and guidance to encourage merit and happiness in their lives. It encourages them to follow the five major Buddhist vow to follow the precepts (five rules of conduct):
· You shall not kill lives
· You shall not steal or cheat
· You shall not commit adultery
· You shall not lie
· You shall not consume alcohol or drugs

The rule is that for three months during the rainy season the monks must vow not to stay overnight away from their temple, unless they have permission for special circumstances such as visiting sick parents, going to deliver sermons. In any case, they can never be gone more than seven days.

On the first day of the waning moon, People do Tak baat (Alms offerings) of food (particularly khaotom, rice, banana or pork wrapped in banana leaves) and donate necessities like soap, toothpaste and toothbrushes and towels for the monks. Most temples are very busy during this time with people making merit and giving their donations. At the end of these merit-making activities the monks will recite the teachings of Buddha and tell the history of Lent to temple goers., take the precepts, and listen to a sermon. After the evening prayers, the novices and monks make their vows to stay in their wat and kuti or monk living quarters , residence, for the three rainy months.
On the full-moon day of the eighth lunar month people go to the temple with incense sticks, candles, and Pha Ab Nam Fon (a yellow robe for bathing) and offer them to the Buddha statue in the temple. After that, they perform the prayer/chanting ceremony and listen to a sermon. Later in the evening monks, novices and laypeople bring flowers and candles and walk around the central temple three times in a ceremony known as Vien Thien in Lao.