Meteorological Department Issues Heavy Rain Alert for 33 Provinces
Thailand's Meteorological Department warns of heavy rain across 33 provinces through August 18, with the upper northeast and eastern regions facing severe flooding risks from a strengthening monsoon system over northern Laos and Vietnam.
On August 18, 2025, the Meteorological Department forecasts heavy rain in some areas nationwide, with particularly heavy rainfall expected in the upper northeast and east regions due to a monsoon trough moving across northern Laos and entering a low-pressure zone over northern Vietnam, combined with an intensifying southwest monsoon over the Andaman Sea, Thailand, and the Gulf of Thailand.
Residents in affected areas are urged to be cautious of heavy to very heavy rainfall and accumulated precipitation, which may cause flash floods, flash flooding, and overflowing waterbanks, especially in hillside areas near water channels and lowland zones. Wind and wave conditions in the Andaman Sea and Gulf of Thailand are moderate, with waves in the upper Andaman Sea and upper Gulf of Thailand reaching approximately 2 meters and exceeding 2 meters in areas with thunderstorms. Fishermen are advised to navigate carefully and avoid thunderstorm areas.
Regional forecasts for the next 24 hours:
Northern Region: Thunderstorms covering 40 percent of the area with heavy rainfall in Mae Hong Son, Chiang Mai, Chiang Rai, Phayao, Nan, Lampang, Phrae, and Tak provinces. Lows 22-28°C, highs 32-36°C. Southwest winds 10-20 km/hr.
Northeast Region: Thunderstorms covering 60 percent of the area with heavy rainfall in Nong Khai, Udon Thani, Sakon Nakhon, Kalasin, Mukdahan, Roi Et, Yasothon, Amnat Charoen, Surin, Sisaket, and Ubon Ratchathani provinces, with very heavy rainfall in Bueng Kan and Nakhon Phanom. Lows 24-26°C, highs 33-36°C. Southwest winds 10-20 km/hr.
Central Region: Thunderstorms covering 40 percent of the area, mainly in Kanchanaburi and Saraburi provinces. Lows 24-27°C, highs 35-37°C. Southwest winds 10-25 km/hr.
Eastern Region: Thunderstorms covering 60 percent of the area with heavy rainfall in Nakhon Nayok and Chanthaburi, and very heavy rainfall in Trat province. Lows 22-26°C, highs 31-35°C. Southwest winds 20-35 km/hr. Seas 2 meters, exceeding 2 meters in thunderstorm areas.
Southern Region (East Coast): Thunderstorms covering 30 percent of the area, mainly in Prachuap Khiri Khan, Chumphon, Nakhon Si Thammarat, Yala, and Narathiwat provinces. Lows 23-26°C, highs 33-36°C. Southwest winds 15-35 km/hr. Seas 1-2 meters, 2 meters offshore, exceeding 2 meters in thunderstorm areas.
Southern Region (West Coast): Thunderstorms covering 40 percent of the area, mainly in Ranong, Phang Nga, Trang, and Satun provinces. Lows 23-26°C, highs 31-34°C. From Ranong northward: Southwest winds 20-35 km/hr, seas 2 meters, exceeding 2 meters in thunderstorm areas. From Phang Nga southward: Southwest winds 15-35 km/hr, seas 1-2 meters, exceeding 2 meters in thunderstorm areas.
Bangkok and Vicinity: Thunderstorms expected.
