This tradition originates from old times when Buddha stayed in temples during the rainy season to avoid killing insects or harming the growing seeds. It is a period for study, meditation and teaching of new monks. The monks are allowed to go out during the day but they must sleep in the same temple every night during these three months.
In the old times there was only candle light to be used around the temple, and on the entry of the rainy season, Thai people made large candles as offerings to be used during this season. Some believe that as a result of this custom, they become brighter, and smarter – similar to the characteristics of the candlelight. This tradition passed on from generation to generation and it is still present today.