British expatriates living in Thailand should be aware of significant rainfall expected across the country on Tuesday, September 1, 2026.
Heavy Rainfall Forecast for Eight Thai Provinces
The Thai Meteorological Department (TMD) has issued a warning indicating very heavy rainfall in eight specific provinces. Bangkok and its surrounding areas are also forecast to experience isolated heavy rain.
The provinces facing the most intense downpours are Mae Hong Son, Tak, Nakhon Phanom, Amnat Charoen, Ubon Ratchathani, Nakhon Nayok, Prachin Buri, and Sa Kaeo. This heavy rainfall is predicted to occur over a 24-hour period, from 6 am on Tuesday to 6 am on Wednesday.
These weather conditions are being attributed to a monsoon trough that is moving across the northern and upper northeastern parts of Thailand. This trough is extending towards a weather depression located off the coast of southern China. Complementing this is a strong south-westerly monsoon current that is currently active over the Andaman Sea, Thailand, and the Gulf of Thailand.
Implications for Expats
Residents in the areas identified for very heavy rainfall are being advised by the TMD to prepare for the potential consequences. These include flash floods and surface run-off, particularly in areas situated on slopes, near bodies of water, and in low-lying districts. Expats should be mindful that accumulated rainfall can significantly alter local conditions.
The TMD has also recommended that individuals avoid routes that have a history of flooding. This advice is especially pertinent for low-lying roads where short-term inundation is a possibility.
Northern Thailand
Expats in the northern regions can anticipate thunderstorms covering approximately 70% of the area. Heavy rain is expected in Chiang Mai, Lampang, Lamphun, Uttaradit, Sukhothai, Kamphaeng Phet, Phitsanulok, Phichit, and Phetchabun. Mae Hong Son and Tak are forecast to receive very heavy rainfall. Overnight temperatures are predicted to range between 22-26°C, with daytime highs between 28-33°C. Winds will be south-westerly at 10-20 kilometres per hour.
Northeastern Thailand
Similar to the north, thunderstorms are forecast to affect around 70% of the northeastern region. Heavy rain is anticipated in Loei, Bueng Kan, Sakon Nakhon, Chaiyaphum, Mukdahan, Yasothon, Nakhon Ratchasima, Buri Ram, Surin, and Si Sa Ket. Nakhon Phanom, Amnat Charoen, and Ubon Ratchathani are the provinces expected to experience very heavy rainfall. Temperatures will be between 23-24°C overnight, rising to 27-32°C during the day. South-westerly winds will range from 10-25 km/h.
Central Thailand
The central region is expected to see thunderstorms across 60% of its area. Heavy rain is forecast for Uthai Thani, Lop Buri, Saraburi, and Kanchanaburi. Temperatures will range from 23-25°C overnight to 31-34°C during the day. South-westerly winds will be between 10-25 km/h.
Eastern Thailand
Expats in the eastern provinces should prepare for thunderstorms covering 70% of the region. Rayong, Chanthaburi, and Trat are predicted to have heavy rain, while Nakhon Nayok, Prachin Buri, and Sa Kaeo will experience very heavy falls. Temperatures are expected to be between 23-27°C overnight and 29-34°C during the day. South-westerly winds will be stronger here, ranging from 20-35 km/h. Waves along the coast are forecast to be around two metres, potentially exceeding this during thunderstorms.
Southern Thailand – East Coast
Thunderstorms are expected to cover 40% of the eastern coastal areas of the south, affecting Phetchaburi, Prachuap Khiri Khan, Chumphon, and Surat Thani. Temperatures will range from 23-26°C overnight to 31-36°C during the day. North of Surat Thani, south-westerly winds will be 20-35 km/h, with waves of one to two metres, reaching about two metres offshore and exceeding two metres during thunderstorms. South of Nakhon Si Thammarat, winds will be 15-35 km/h, with waves around one metre, rising to one to two metres offshore and above two metres during thunderstorms.
Southern Thailand – West Coast
The west coast of the south will also experience thunderstorms, affecting about 40% of the region, primarily Ranong, Phang Nga, Trang, and Satun. Overnight temperatures will be between 23-27°C, with daytime highs of 31-35°C. North of Phuket, south-westerly winds will be 20-40 km/h, and waves are expected to reach two to three metres, potentially exceeding three metres during thunderstorms. South of Krabi, winds will be 20-35 km/h, with waves around two metres, and exceeding two metres during thunderstorms.
Bangkok and Surrounding Areas
Expats in Bangkok and its neighbouring provinces should anticipate thunderstorms across 70% of the area, with isolated instances of heavy rain. Temperatures will range from 25-27°C overnight to 31-34°C during the day. South-westerly winds will be between 10-25 km/h.
Maritime Safety Advice
Conditions in the upper Andaman Sea are expected to be rough, with waves ranging from two to three metres, and potentially exceeding three metres during thunderstorms. Waves in the lower Andaman Sea and the upper Gulf of Thailand will be around two metres, with higher waves expected in stormy areas. Mariners operating small boats in the upper Andaman Sea are specifically advised to remain ashore. All mariners in the Andaman Sea and Gulf of Thailand should exercise caution and avoid thunderstorms.
Tropical Storm Saudel Update
A separate weather system, Tropical Storm Saudel, which has formed over the upper South China Sea, is forecast to approach Taiwan between Thursday and Friday, September 3-4. The TMD has stated that this storm is not expected to move into Thailand. However, British nationals who are planning travel to Taiwan or surrounding areas should monitor the latest weather advisories before their departure.
Reviewed by the Thailand Guide Editorial Team • Last reviewed: 1 September 2026
This page is provided for general information only. While we aim for accuracy, details can change — please verify anything important independently before relying on it.
