Buddhist Lent Day in Thailand is the day after Asalha Bucha marking the beginning of the three month period where monks stay in their temples with no travelling.
Celebration\ Observance
The city of Ubon has a candle festival with a parade and candle design competition. During lent candles are kept burning. This day is a national holiday with some government and businesses closed.
History
This holiday has been celebrated and observed over thousands of years.