BANGKOK — 3 June 2026, Thailand’s Meteorological Department has warned of heavy to very heavy rainfall across 40 provinces, with parts of the south, east, and the Bangkok metropolitan area expected to experience widespread thunderstorms.
In its 24-hour forecast, the department said the eastern region and southern Thailand would face the heaviest conditions, while parts of the northern and central regions, including Bangkok and surrounding provinces, could also see isolated heavy downpours.
Authorities urged residents in vulnerable areas to remain alert for possible flash floods and runoff, particularly in low-lying locations and near waterways.
Bangkok and neighbouring provinces are forecast to experience thunderstorms across 60% of the area, with some districts likely to receive heavy rain. Temperatures are expected to range from 26-28 degrees Celsius overnight to 34-36 degrees Celsius during the day.
In northern Thailand, thunderstorms are expected in about 40% of the region, with heavy rain forecast in Mae Hong Son, Tak and Kamphaeng Phet provinces.
The northeast is also expected to see thunderstorms across 40% of the region, affecting provinces including Nong Khai, Bueng Kan, Udon Thani, Sakon Nakhon, Nakhon Phanom, Chaiyaphum, Kalasin, Mukdahan, Nakhon Ratchasima, Buri Ram and Ubon Ratchathani.
Central Thailand is forecast to experience thunderstorms across 40% of the region, with heavy rain possible in Uthai Thani, Kanchanaburi, Ratchaburi, Suphan Buri and Nakhon Pathom.
The eastern region is expected to be among the hardest hit, with thunderstorms forecast across 60% of the area and heavy to very heavy rainfall likely in Nakhon Nayok, Prachin Buri, Chon Buri, Rayong, Chanthaburi and Trat.
Sea conditions in the east are expected to be rough, with waves reaching 2-3 metres and exceeding 3 metres in thunderstorm areas.
On the Gulf coast, thunderstorms are forecast across 60% of southern eastern provinces, with heavy rain expected in Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung and Songkhla.
The Andaman coast is forecast to experience the most severe weather, with thunderstorms covering 80% of the region and heavy to very heavy rain expected in Ranong, Phangnga, Phuket, Krabi, Trang and Satun.
Waves in the Andaman Sea are expected to reach 2-3 metres and exceed 3 metres during thunderstorms, prompting warnings for mariners to exercise caution.