Thailand is set to experience significant rainfall across a large portion of the country on September 15, 2026, with the Thai Meteorological Department issuing warnings for heavy downpours in 47 provinces. The capital city, Bangkok, can anticipate widespread showers and isolated instances of heavy rain, with temperatures ranging from a low of 24°C to a high of 34°C.
National Weather Overview
The current weather pattern is influenced by a monsoon trough extending across the Central and Northeastern regions of Thailand. Complementing this, a moderate southwest monsoon is active over the Andaman Sea, the mainland, and the southern Gulf of Thailand. This combination is expected to bring considerable moisture and instability, leading to the widespread precipitation.
Specific areas are at higher risk for more intense rainfall. The Eastern regions are forecast to receive isolated heavy to very heavy rains. Meanwhile, other parts of the country may experience isolated heavy rain events.
Regional Forecasts
Bangkok Metropolitan Area
Residents and visitors in Bangkok should prepare for fairly widespread thundershowers and the possibility of localized heavy rain. The minimum temperature is expected to be between 24-25°C, with a maximum of 32-34°C. Winds will be from the southwest at 10-20 km/h.
Northern Thailand
Scattered thundershowers and isolated heavy rain are predicted for the North, affecting provinces such as Mae Hong Son, Chiang Mai, Tak, Kamphaeng Phet, Phitsanulok, Phichit, Phetchabun, Nan, and Uttaradit. Temperatures in the North will vary from 22-27°C at night to 30-36°C during the day. Easterly winds are expected at 10-20 km/h.
Northeastern Thailand
The Northeast is also under a significant rain alert, with fairly widespread thundershowers and isolated heavy rain anticipated across numerous provinces. These include Loei, Nong Bua Lamphu, Nong Khai, Bueng Kan, Udon Thani, Sakon Nakhon, Nakhon Phanom, Chaiyaphum, Khon Kaen, Kalasin, Mukdahan, Maha Sarakham, Roi Et, Yasothon, Amnat Charoen, Nakhon Ratchasima, Buriram, Surin, Sisaket, and Ubon Ratchathani. Nighttime temperatures will be between 22-23°C, rising to 27-31°C in the daytime. Southwesterly winds will blow at 10-25 km/h.
Central Thailand
Central Thailand will experience fairly widespread thundershowers and isolated heavy rain. Provinces affected include Nakhon Sawan, Uthai Thani, Chai Nat, Sing Buri, Ang Thong, Lop Buri, Saraburi, Phra Nakhon Si Ayutthaya, Suphan Buri, Kanchanaburi, and Ratchaburi. The temperature range is from 23-25°C overnight to 31-35°C during the day, with southwesterly winds at 10-20 km/h.
Eastern Thailand
The East faces the prospect of isolated very heavy rain, particularly in Chanthaburi and Trat. Other areas like Nakhon Nayok, Prachinburi, Chachoengsao, Chonburi, and Rayong will see fairly widespread thundershowers and isolated heavy rain. Temperatures will range from 24-27°C overnight to 28-33°C during the day. Southwesterly winds will be stronger here, at 15-35 km/h. Wave heights in the Gulf of Thailand are expected to be 1-2 meters, potentially exceeding 2 meters in areas with thundershowers.
Southern Thailand (East Coast)
The east coast of the South will see scattered thundershowers, primarily affecting Phetchaburi, Prachuap Khiri Khan, Chumphon, Pattani, Yala, and Narathiwat. Overnight temperatures are forecast between 23-26°C, with daytime highs reaching 31-36°C. Southwesterly winds will be at 15-35 km/h. Wave heights are expected to be around 1 meter, reaching 1-2 meters offshore and potentially over 2 meters during thundershowers.
Southern Thailand (West Coast)
The west coast of the South, including Ranong, Phang Nga, and Phuket, is forecast to experience scattered thundershowers and isolated heavy rain. Temperatures will range from 23-26°C overnight to 30-34°C during the day. Southwesterly winds will be 15-35 km/h. Similar to the east coast, wave heights are expected to be 1-2 meters, and above 2 meters in areas experiencing thundershowers.
Severe Weather Warnings
The Thai Meteorological Department has issued a stern warning to the public. Residents are urged to exercise caution due to the potential for heavy to very heavy rainfall. The accumulation of water could lead to flash floods, river overflows, and landslides, particularly in areas near foothills, along waterways, and in low-lying regions. Preparedness is advised for all affected provinces.
