The Songkran festival is the traditional Thai New Year's Day and is celebrated from 13 April to 15 April.
The word Songkran is from the Sanskrit language and means the passage of the sun from one sign of the Zodiac to another. That means there are twelve Songkrans each year, but the significance of the this Songkran (sometimes called Major Songkran to distinguish it from the others) is when the sun enters the sign of Aries the Ram. The particular event was also closely related to the Vernal Equinox.
Celebrating New Year at the time of the Vernal Equinox was very common in the past. The Songkran celebration is similar to those of the Indian Holi Festival, the Chinese Ching Ming, and the Christian Festival of Easter. Indeed April Fool's Day probably originated as mocking those who didn't accept the switch of New Year from April to January in France in the Sixteenth Century.
In ancient times, the dates of Songkran and the Vernal Equinox would have been closer, but they have shifted due to an effect called procession, where the Earth wobbles on it's axis over a 25,000 year period.
The date was originally set by astrological calculations, but it is now fixed on 13 April. The festival may be extended if some of the celebrations fall over a weekend.
In Thailand, New Year is now officially celebrated on January 1, in line with almost all other countries. Songkran was the official New Year until 1888, when it was switched to a fixed date of 1 April. It wasn't until 1940, that this date was then shifted to 1 January.
Making a splash
The most famous aspect of the Songkran celebrations is the throwing of water. The custom originates from spring cleaning aspect of Songkran. Part of the ritual was the cleaning of images of Buddha. Using the 'blessed' water that cleaned the images to soak other people is seen as a way of paying respect and bring good fortune.
It also doesn't hurt that April is the hottest part of the year in Thailand, so being soaked is a refreshing escape from the heat and humidity.
Nowadays Thais will walk the streets having 'water fights' using containers of water or water guns, or stand at the side of roads with a hose and soak any one who passes by.
You may also get covered in chalk, a custom originating from the chalk used by monks to mark blessings. This combination of water and powder is almost identical to the celebrations of Holi, and indeed, it maybe that the customs originated in India as certainly Songkran is celebrated more widely and longer in the Northern part of Thailand.
Even more interesting is that the custom of water fights pops up in a distant place at the same time of year. Dyngus Day is celebrated on Easter Monday in Poland, and on the Monday the custom is that boys get to soak girls with water, but on the Tuesday, the girls get to throw crockery at the boys - again the water and powder combination.
As mentioned, Songkran is a Spring Cleaning Day, both physically and spiritually. On the physical side, in addition to cleaning other customs are that anything old and useless must be thrown away or else it will bring bad luck to the owner. On the spiritual side, some people make New Year resolutions.