Wikipedia
Kathina
Kathina is a Buddhist festival which comes at the end of Vassa, the three-month rainy season retreat for Theravada Buddhists. The season during which a monastery may hold Kathina is one month long, beginning after the full moon of the eleventh month in the Lunar calendar (usually October).
It is a time of giving, for the laity to express gratitude to bhikkhus (Buddhist monks). Lay Buddhists bring donations to temples, especially new robes for the monks.