Revellers can expect hot weather during the Songkran festival followed by gusty winds and thunderstorms, the Meteorological Department has warned.
The weather forecast called for high temperatures and overcast skies until Friday followed by strong winds and storms in all regions except the South.
The northern and northeastern regions could see the mercury reach 40°C in Mae Hong Son, Lampang, Tak and Buri Ram during the Thai New Year celebration that started on Wednesday.
Temperatures in Greater Bangkok could go up to 39°C, with Pathum Thani the hottest province.
Lampang, neighbouring Sukhothai and Uthai Thani were the hottest places on Tuesday as temperatures went up to 40°C, according to the department's latest data.
The country will end the long break with summer storms over the weekend.