The heat index – a measure of what the temperature feels like taking into account humidity, wind speed and other factors – was at an “extremely dangerous” level in Bangkok, the city’s environment department warned.
Authorities in Udon Thani province, in the kingdom’s rural northeast, also warned of blazing temperatures on Thursday.
The health ministry said late Wednesday that 30 people had died from heatstroke between Jan 1 and Apr 17, compared with 37 in the whole of 2023.
Direk Khampaen, deputy director-general of Thailand’s Department of Disease Control, told AFP that officials were urging elderly people and those with underlying medical conditions including obesity to stay indoors and drink water regularly.