phansa

The vassa, or rainy-season retreat, is a significant Buddhist monastic observance primarily in Southeast Asian Buddhist communities. It occurs annually during the three-month monsoon period, typically from July to October.12

This tradition likely originated from an ancient custom of ascetics retreating to sheltered areas during the monsoon when travel was difficult. The Buddha himself is said to have observed this practice. His followers continued this tradition after his death, gathering to recite monastic rules and reaffirm their commitment to Buddhist teachings. Over time, permanent monastic centers, known as viharas, were built to house monks during these retreats.1

In countries like Thailand, it's common for laymen to temporarily take monastic vows for the vassa period. A monk's seniority is often measured by the number of vassa seasons they have completed. The retreat concludes with the pavarana ceremony, where monks agree to accept correction from others. Following vassa, the kathina ceremony involves laypeople presenting gifts, such as robes, to the monks. This practice is largely observed in Theravada Buddhism and has been less common among Mahayana Buddhists.21