Go to the Yi Peng Festival

Yi Peng refers to the full moon day in the second month according to the Lanna lunar calendar (the twelfth month of the Thai lunar calendar).[9] The festival is meant as a time to make merit(Thai: ทำบุญ; RTGS: tham bun).   Yi means “two” and peng means a “full moon day”.
Swarms of sky lanterns (Thai: โคมลอย; RTGS: khom loi), literally: ‘floating lanterns’, are launched into the air. Khom loi are made from a thin fabric, such as rice paper, stretched over a bamboo or wire frame, to which a candle or fuel cell is attached. When the fuel cell is lit, the resulting hot air is trapped inside the lantern and creates enough lift for the khom loi to float into the sky.
Because they are a hazard to passing aircraft and “…can cause damage to important places in the areas such as the Grand Palace [sic], temples and governmental offices,…” khom loi are increasingly subject to governmental restrictions. In Chiang Mai, authorities cancelled 78 flights in and out of Chiang Mai Airport on 3–4 November 2017. Another 79 flights were rescheduled. In Bangkok, the public are prohibited from using fireworks and sky lanterns entirely. Violators may face three years imprisonment and/or a fine of 60,000 baht. One hundred-ninety piers on the Chao Phraya River will be open to the public to float their krathongs.
During the festival, some people also decorate their houses, gardens, and temples with khom fai (Thai: โคมไฟ), intricately shaped paper lanterns which take on different forms. Khom thue (Thai: โคมถือ) are lanterns which are carried around hanging from a stick, khom khwaen (Thai: โคมแขวน) are the hanging lanterns, and khom pariwat(Thai: โคมปริวรรต), which are placed at temples and which revolve due to the heat of the candle inside. The most elaborate Yi Peng celebrations can be seen in Chiang Mai, the ancient capital of the former Lanna kingdom, where now both Loi Krathong and Yi Peng are celebrated at the same time resulting in lights floating on the waters, lights hanging from trees/buildings or standing on walls, and lights floating in the sky. The tradition of Yi Peng was also adopted by certain parts of Laos during the 16th century.