The Thai Meteorological Department forecasts heavy rain in 53 provinces today, 21 September 2026. Bangkok can expect fairly widespread showers and isolated heavy rain, with lows and highs of 24-33°C. Very heavy rain is possible in Chachoengsao, Chanthaburi, Chon Buri, Nakhon Nayok, Prachin Buri, Rayong, Sa Kaeo, Trat.
The high-pressure system from China covers the upper North and the upper Northeast. Meanwhile the monsoon trough lies across the lower Central the upper South and the East regions into the active low-pressure cell over the middle South China Sea with the moderate southwest monsoon prevails over the Andaman Sea, the South and the Gulf with isolated heavy rains in the country while isolated very heavy rain are possible in the East.
Bangkok
Fairly widespread thundershowers and isolated heavy rain. Minimum temperature 24-26°C. Maximum temperature 31-33°C. Variable winds 10-25 km/h.
North
Fairly widespread thundershowers and isolated heavy rain in Chiang Mai, Chiang Rai, Lampang, Sukhothai, Tak, Uttaradit, Kamphaeng Phet, Phichit, Phitsanulok, and Phetchabun. Minimum temperature 21-26°C. Maximum temperature 32-35°C. Easterly winds 10-20 km/h.
Northeast
Fairly widespread and isolated heavy rain in Loei, Chaiyaphum, Khon Kaen, Maha Sarakham, Roi Et, Mukdahan, Yasothon, Amnat Charoen, Nakhon Ratchasima, Buri Ram, Surin, Si Sa Ket, and Ubon Ratchathani. Minimum temperature 22-24°C. Maximum temperature 31-34°C. Easterly winds 10-20 km/h.
Central
Fairly widespread thundershowers and isolated heavy rain in Nakhon Sawan, Uthai Thani, Chai Nat, Lop Buri, Saraburi, Suphan Buri, Phra Nakhon Si Ayutthaya, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Songkhram, and Samut Sakhon, Minimum temperature 23-25°C. Maximum temperature 32-34°C. Southeasterly winds 10-25 km/h.
East
Fairly widespread thundershowers and isolated heavy rain in Sa Kaeo, Chachoengsao, Chon Buri, Rayong, Chanthaburi, and Trat Isolated very heavy rain in Nakhon Nayok and Prachin Buri. Minimum temperature 23-25°C. Maximum temperature 30-34°C. Variable winds 20-35 km/h. Wave height about 2 meters and above 2 meters in thundershowers.
South (east coast)
Fairly widespread thundershowers and isolated heavy rain in Phetchaburi, Prachuap Khiri Khan, Chumphon, Phatthalung, Songkhla, Pattani, Yala, Narathiwat, Minimum temperature 22-25°C. Maximum temperature 31-34°C. From Surat Thani northward: Variable winds 20-35 km/h. Wave height 1-2 meters about 2 meters offshore and above 2 meters in thundershowers. From Nakhon Si Thammarat southward: Southwesterly winds 15-35 km/h. Wave height about 1 meter, 1-2 meters offshore and above 2 meters in thundershowers.
South (west coast)
Scattered thundershowers and isolated heavy rain in Ranong, Phang Nga, Phuket, and Krabi Minimum temperature 23-25°C. Maximum temperature 30-33°C. From Phang-nga northward: Southwesterly winds 20-35 km/h. Wave height about 2 meters and above 2 meters in thundershowers. From Phuket southward: Southwesterly winds 15-35 km/h. Wave height 1-2 meters and above 2 meters in thundershowers.
Warnings
People should beware of heavy to very heavy rains and accumulation that may cause flash floods, overflows and landslides especially along the waterways near foothills and lowlands.
Source: Thai Meteorological Department daily forecast, announcement of 21 September 2026.
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