Chol Vassa: Buddhist Lent in Cambodia

Every year, on the day after the full moon of the month of Asadh, monks across Cambodia begin Vassa, the rains retreat. For about three lunar months they stay at their own monastery to study, meditate and teach. Lay families visit the pagoda more often, and many quietly change their plans for the season.

This guide explains where the custom comes from, how its dates are worked out, what families in Cambodia traditionally do during these months, and why the start date moves so much from year to year. There is a table for 2024 to 2030 and a checker for any date.

In the Buddha's time, monks walked from village to village all year. Buddhist texts tell that during the rainy season people complained: wandering monks trampled young rice plants and small creatures in the wet fields. The Buddha then asked monks to stay in one place for the three months of the rains.

The rule is still followed. A monk who enters Vassa promises to spend the season at one monastery. He may leave for up to seven days for a real need, such as caring for a sick parent, but he must return before the seventh dawn. A monk's seniority is still counted in the number of Vassa seasons he has completed.

The Khmer lunar year is about 11 days shorter than the solar year, so Chol Vassa usually comes about 11 days earlier than the year before. To stop the months drifting away from the seasons, the calendar adds a leap month (Adhikameas) every two or three years by repeating Asadh.

That is why the dates swing: in 2025 Vassa began on 11 July 2025, but 2026 had two Asadh months, so it began almost three weeks later, on 30 July 2026. The next leap year in the table is 2029.

Many Cambodian families do not hold weddings during the three months of Vassa, and the wedding season traditionally picks up again after Chenh Vassa. The Buddhist rule binds the monks, not lay people, so this is a family custom rather than a religious law. How strictly it is kept differs between families and regions, so ask your elders or the achar who will lead the ceremony.

If you are using our Wedding Date tool, it does not check Vassa. Compare the months it suggests with the table above, or test a date in the checker below. For example, any date from 30 July 2026 to 26 October 2026 falls inside the 2026 retreat.

The same thinking is often applied to housewarmings and shop openings, which families tend to plan for the dry season. Our guide to lucky days to open a business covers how Cambodian families choose those days.

Read next: how the Khmer lunar calendar counts waxing and waning days, when the Khmer animal year changes, or try the Zodiac Checker to see your own Khmer lunar birth date.