The fireballs are most often reported around the night of Wan Ok Phansa at the end of Buddhist Lent in late-October. Naga fireballs have been reported over an approximately 250 km (160 mi) long section of the Mekong River centered approximately on Phon Phisai in the Phon Phisai District. Fireballs have also been reported rising from smaller rivers, lakes and ponds in the region. The fireballs were called "ghost lights" by locals until the mid-1980s, when the local council officially named them "phaya nak lights". In 2018 one observer noted that while the light phenomenon is "hundreds of years old", the new name Phaya Nak lights is only about 35 years old."