Yasothon's rocket festival ประเพณีบุญบั้งไฟ Prapheni Bun Bang Fai |Tradition of Boon of Bong of Fire) is held annually over the weekend that falls in the middle of the month of May. The festival's origins lie in a custom of firing rockets into the sky at the start of the rice-growing season to remind King of the Sky, Phaya Thaen, to send promised rain. The festival is a competition marked by a weekend of celebration, including highly-decorated floats parading through the town, accompanied by partying, dancing, music, and a fair. Friday the main thoroughfare is transformed into a parade ground lined on both sides by concert stages, which will feature Mor lam performers throughout the night. Saturday sponsored parade groups compete for prizes. Many of the traditional dances and floats have to do with the legend of Nang Ai and Phadaeng, but others have to do with that year's particular theme.
Sunday the action moves from the city center to Phaya Thaen Park at its eastern edge. The park is not only a beautiful playground with an athletic stadium and outdoor stage, it is also part of the city's flood-control project for those times when Phaya Thaen sends too much rain.
The festival now takes the form of a competition to see whose rocket will stay aloft for the longest time.
On May 10, 1999, the Yasothon Rocket Festival made world headlines when a 120 kg rocket exploded 50 meters above ground, just two seconds after launch, killing five persons and wounding 11.