The mercury rose to 40 degrees Celsius in Bangkok on Thursday while 35 provinces in upper Thailand also experienced hot to very hot spells amid risk of brewing summer storms.
The Thai Meteorological Department warned residents to avoid outdoor activities and beware of gusty winds by staying away from big trees, unsecured buildings, and billboards.
The department pointed to the hot low pressure cell covering upper Thailand and the southerly and southeasterly winds prevailing over the North, the Northeast, the Central, the East, and the South regions throughout this week. It said the upper regions would suffer hot to very hot weather.
Greater Bangkok saw temperatures in the range of 37-40 degrees Celsius, the North was at 39-43, the Northeast at 37-41, the Central at 37-42 and the East at 34-39.
Outbreaks of thundershowers with gusty winds were forecast for the lower North, the Northeast, the Central and the East. In the South, where the maximum temperature is 33-37 degrees Celsius, there will likely be isolated thundershowers, the department added.