The centre said the "very" hot weather was caused by a warm low pressure over upper Thailand, combined with the current haze crisis in the area.
Many provinces, including Lamphun, Lampang, Mae Hong Son, Tak, Petchabun, Sukhothai, will face up to 40 degree Celsius.
In the past 24 hours, the highest temperature was recorded at both Lampang's Thoen district and Bhumibol Dam in Tak province at nearly 41 degree Celsius.
The "very" hot weather will continue for a while and people's health could be affected as the region is also encountering haze and forest fire problems.
Local residents were advised to avoid exposure to sun for too long and to drink more water to avoid any health risks. (MCOT online news)