This weekend is Songkran, the Thai New Year festival. The date for Thai New Year’s Day is 13 April every year, but the holiday period also includes 14–15 April. The word Songkran comes from the Sanskrit word, literally “astrological passage”, meaning transformation or change. This famed festive occasion is in keeping with the Buddhist/Hindu solar calendar. The holiday is renowned for it’s water festival which is mostly celebrated by young people. Major streets are closed for traffic, and many are used as arenas for water fights. Celebrants, young and old, participate in this tradition by splashing water on each other. Traditional parades are held and in some venues and “Miss Songkran” is crowned.

Information from Wikipedia.