Heavy Rain Warning for 21 Provinces as Monsoon Strengthens
Thailand's Meteorological Department warns of heavy rain across 21 provinces through August 15, with very heavy rainfall expected in the East and risks of flash floods and river overflows, particularly in low-lying areas and near waterways.
BANGKOK — 14 August 2026, Thailand will continue to experience heavy rain in some areas over the next 24 hours, with very heavy rain forecast for parts of the East, according to the Meteorological Department.
The department said that a monsoon trough is extending across Myanmar, upper Laos and upper Vietnam, while a relatively strong southwesterly monsoon is prevailing over the Andaman Sea, Thailand and the Gulf of Thailand.
Residents in affected areas have been warned to watch out for the dangers posed by heavy and accumulated rainfall, which could trigger flash floods and forest runoff, particularly in foothill areas, near waterways and in low-lying areas. Rivers may also overflow in parts of the Northeast.
Winds and waves in the upper Andaman Sea will be relatively strong, with waves reaching 2-3 metres and rising above 3 metres in areas experiencing thunderstorms.
The Meteorological Department advised boat operators to exercise caution and avoid areas experiencing thunderstorms. Small boats in the upper Andaman Sea should remain ashore.
Weather forecast from 07:00 on 14 August to 07:00 on 15 August
North: Thunderstorms will cover 60% of the area, with isolated heavy rain in Mae Hong Son, Nan and Tak. Temperatures will range from 22-28°C, with highs of 32-35°C. Southwesterly winds will blow at 10-20km/h.
Northeast: Thunderstorms will cover 60% of the area, with isolated heavy rain in Udon Thani, Nong Khai, Bueng Kan, Sakon Nakhon, Nakhon Phanom and Mukdahan. Temperatures will range from 24-26°C, with highs of 32-35°C. Southwesterly winds will blow at 10-20km/h.
Central: Thunderstorms will cover 40% of the area, with isolated heavy rain in Saraburi and Kanchanaburi. Temperatures will range from 24-27°C, with highs of 34-36°C. Southwesterly winds will blow at 10-25km/h.
East: Thunderstorms will cover 60% of the area, with isolated heavy rain in Nakhon Nayok and Prachinburi, and very heavy rain possible in Chanthaburi and Trat. Temperatures will range from 24-28°C, with highs of 30-34°C. Southwesterly winds will blow at 20-35km/h. Waves will be around 2 metres, rising above 2 metres during thunderstorms.
South, east coast: Thunderstorms will cover 40% of the area, mainly in Chumphon, Surat Thani and Nakhon Si Thammarat. Temperatures will range from 23-26°C, with highs of 31-36°C. Southwesterly winds will blow at 20-35km/h. Waves will be 1-2 metres offshore, around 2 metres farther from the coast and above 2 metres during thunderstorms.
South, west coast: Thunderstorms will cover 60% of the area, with isolated heavy rain in Ranong and Phang Nga. Temperatures will range from 23-27°C, with highs of 31-36°C.
From Phang Nga northwards, southwesterly winds will blow at 20-40km/h, with waves of 2-3 metres and waves above 3 metres during thunderstorms.
From Phuket southwards, southwesterly winds will blow at 15-35km/h, with waves of 1-2 metres and waves above 2 metres during thunderstorms.
