TMD forecasts heavy rain in 3 Thai regions on October 17, with wider downpours expected on October 21–25
Heavy to very heavy rain is forecast in southern and eastern Thailand on October 18–20, with more regions at risk on October 21–25.
- The Thai Meteorological Department (TMD) forecasts isolated heavy rain on October 17 in the Central, Eastern, and Southern regions, with risks of flash floods.
- A more widespread period of heavy to very heavy rain is expected from October 21–25, affecting the lower Northeast, Central region, Bangkok, East, and upper South.
- In the interim, from October 18–20, Southern and Eastern Thailand are predicted to face persistent heavy to very heavy rainfall.
The Thai Meteorological Department (TMD) warned at 5am Thailand time on October 17, 2026, of isolated heavy rain in three regions: Central, Eastern and Southern Thailand. The next 24 hours bring risks of flash floods and forest run-off, while a further spell of heavy rain is forecast to affect more areas on October 21–25.
The TMD urged people in the three regions to watch for thunderstorms, gusty winds and accumulated rainfall, particularly on foothill slopes near waterways and in low-lying areas.
A weak high-pressure system, or cool air mass, over the upper North, upper Northeast and South China Sea is bringing easterly and southeasterly winds that carry moisture from the South China Sea across Thailand and the Gulf of Thailand, according to the TMD.
South and East face heavy to very heavy rain on October 18–20
The TMD forecasts persistent rain in Southern and Eastern Thailand on October 18–20, with heavy to very heavy falls in some areas. A monsoon trough over the lower South and the southwest monsoon over the lower Andaman Sea will drive the wet conditions.
Rainfall is expected to increase on October 21–25 across the lower Northeast, Central region, Bangkok and surrounding provinces, East and upper South, the TMD said. Some areas face heavy to very heavy rain and gusty winds.
For October 21–25, the TMD expects the monsoon trough to move northwards across the upper South, upper Gulf of Thailand and East. Meanwhile, a high-pressure system from China will extend over the upper North, upper Northeast and South China Sea.
Bangkok forecast puts thunderstorm coverage at 60% on October 17–18
The TMD forecasts thunderstorms over 60% of Bangkok and surrounding provinces, with isolated gusty winds, from 6am on October 17 to 6am on October 18, Thailand time (UTC+7). The regional forecasts below cover the same period; percentages refer to the area expected to experience thunderstorms.
North: Thunderstorms are forecast over 30% of the region, with isolated gusty winds, mainly in Mae Hong Son, Chiang Mai, Tak and Kamphaeng Phet. Minimum temperatures will range from 21–26°C and maximums from 34–36°C.
Northeast: Thunderstorms are forecast over 20% of the region, with isolated gusty winds, mainly in Loei, Chaiyaphum, Nakhon Ratchasima, Buriram and Surin. Minimum temperatures will range from 21–24°C and maximums from 33–35°C.
Central: Thunderstorms are forecast over 40% of the region, with isolated heavy rain and gusty winds in Lopburi, Saraburi, Suphanburi, Phra Nakhon Si Ayutthaya, Kanchanaburi, Ratchaburi and Nakhon Pathom. Minimum temperatures will range from 23–25°C and maximums from 33–36°C.
East: Thunderstorms are forecast over 60% of the region, with isolated heavy rain in Nakhon Nayok, Chonburi, Rayong, Chanthaburi and Trat. Minimum temperatures will range from 24–26°C and maximums from 33–35°C. Waves will be below one metre, exceeding two metres in thunderstorms.
South, east coast: Thunderstorms are forecast over 60% of the area, with isolated heavy rain in Chumphon, Surat Thani, Nakhon Si Thammarat, Songkhla, Yala and Narathiwat. Minimum temperatures will range from 23–25°C and maximums from 32–35°C. Waves will be around one metre, exceeding two metres in thunderstorms.
South, west coast: Thunderstorms are forecast over 60% of the area, with isolated heavy rain in Ranong, Phang Nga, Phuket, Krabi, Trang and Satun. Minimum temperatures will range from 23–25°C and maximums from 32–36°C. Waves will be around one metre, exceeding two metres in thunderstorms.
Bangkok and surrounding provinces: Thunderstorms are forecast over 60% of the area, with isolated gusty winds. Minimum temperatures will range from 26–27°C and maximums from 33–35°C.
Storm waves may exceed two metres in the Andaman Sea and Gulf
For the October 17–18 forecast period, the TMD warned that waves in the Andaman Sea and Gulf of Thailand could exceed two metres in thunderstorms. Mariners should check their routes, navigate cautiously and avoid areas experiencing thunderstorms.
The TMD urged the public to follow forecasts closely throughout October 18–25, when heavy to very heavy rain and accumulated rainfall could cause flash floods and forest run-off.
