Vassana or Vassa is the three-month annual Rains Retreat observed by Theravāda monastic Saṅgha.
Taking place during the wet monsoon season in India, Vassa lasts for three lunar months, usually from July to October.
For the duration of Vassa, monastics remain in one place, typically in monasteries or temple grounds. In many monasteries the Saṅgha dedicate the Vassa to intensive meditation. Lay Buddhists are encouraged to support the Saṅgha, especially during this period.
Some Buddhist laity also choose to observe Vassa by adopting more ascetic practices, such as giving up meat, alcohol, or smoking.
Commonly, the number of years a monk or nun has spent in monastic life is expressed by counting the number of vassas he/she has observed.
Vassa begins on the first day of the waning moon of the eighth lunar month, which is the day after Āsālha Pūjā or Āsālha Uposatha (“Dhamma day”). It ends on Pavāraṇā, when the Saṅgha comes together and atone for any offense that might have been committed during Vassa.
Vassa is followed by Kathina, a festival in which the laity expresses gratitude to the Saṅgha. Lay Buddhists bring donations to temples and monasteries, especially new robes for the Saṅgha.
– Notes on Vassa and Kathina at this link …
– Posted by CFFong