Thingyan is the Myanmar New Year festival that usually occurs in middle of April. It is a Buddhist festival celebrated over a period of four to five days, culminating in the New Year. The dates of the Thingyan Festival are calculated according to the Burmese calendar. The dates of the festival are observed as public holidays throughout Myanmar, and are part of the summer holidays at the end of the school year. Water-throwing or dousing one another from any shape or form of vessel or device that delivers water is the distinguishing feature of this festival and may be done on the first four days of the festival.
Read More about on wikipedia