Thailand faces heavy rain and flood risks until October 25
Bangkok and several Thai regions face heavier rain on October 21–25, with flash floods and landslides possible near waterways and in low-lying areas.
- The Thai Meteorological Department (TMD) has issued a warning for heavy to very heavy rain in parts of Thailand, effective until October 25.
- Waves are forecast to exceed three metres in thunderstorm areas of the Andaman Sea and the Gulf of Thailand during this period.
- Affected regions include the South, East, Central, lower Northeast, and Bangkok, with the TMD cautioning against potential flash floods, run-off, and mudslides.
- Mariners are advised to navigate with caution and avoid sailing through thunderstorms due to the high waves.
The Thai Meteorological Department (TMD) issued its seventh heavy-rain warning on Tuesday (October 20, 2026), alerting parts of Thailand to heavy to very heavy downpours through October 25. The warning also forecasts waves above three metres in thunderstorm areas of the Andaman Sea and Gulf of Thailand.
Southern and eastern Thailand are expected to experience persistent rain on October 20, with heavy to very heavy downpours in some areas, according to the TMD.
Bangkok faces heavier rain from October 21
Bangkok and surrounding provinces are among the areas where rainfall will increase during October 21–25. The TMD forecasts isolated heavy to very heavy rain and strong gusts in the lower Northeast, the Central region, the East and the upper South during the same period.
The TMD warned that prolonged and accumulated rainfall could cause flash floods, sudden run-off and mudslides, particularly on foothill slopes near waterways and in low-lying areas. Residents in the affected regions should also watch for strong gusts.
People travelling during the warning period should avoid routes prone to repeated flooding, especially low-lying stretches where water may accumulate, the TMD advised. Residents should plan journeys and daily activities carefully and monitor subsequent weather announcements.
The TMD attributed the wet conditions to a monsoon trough extending across the middle South, combined with the southwest monsoon over the lower Andaman Sea.
A high-pressure system, or cold air mass, from China is also expected to extend over the upper North, the upper Northeast and the South China Sea, bringing easterly winds over Thailand and the Gulf of Thailand.
Storm waves may exceed three metres in Thai waters
The TMD’s warning through October 25 forecasts waves above three metres in areas of the Andaman Sea and Gulf of Thailand affected by thunderstorms. Mariners should navigate cautiously and avoid sailing through thunderstorms.
The separate 24-hour regional forecast for October 20 gives lower normal wave heights, with waves exceeding two metres in thunderstorms. The figures apply to the daily outlook detailed below.
Thunderstorms forecast over 70% of both southern coastal regions
The TMD’s daily forecast puts thunderstorm coverage at 70% of the area on each coast of southern Thailand, with isolated very heavy rain in several provinces. The regional outlook for October 20 is as follows:
North: Thunderstorms are forecast over 10% of the region, mainly in Mae Hong Son and Tak. Minimum temperatures will range from 21–25°C and maximum temperatures from 34–35°C, with easterly winds of 10–20km/h.
Northeast: Thunderstorms are expected over 20% of the region, mainly in Nakhon Ratchasima, Buri Ram, Surin, Si Sa Ket and Ubon Ratchathani. Minimum temperatures will be 22–24°C and maximum temperatures 33–35°C, with easterly winds of 10–20km/h.
Central region: Thunderstorms will cover 60% of the area, mainly in Phra Nakhon Si Ayutthaya, Suphan Buri, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Sakhon and Samut Songkhram. Minimum temperatures will range from 24–26°C and maximum temperatures from 33–35°C, with easterly winds of 10–20km/h.
East: Thunderstorms are forecast over 60% of the region, with isolated heavy rain in Chon Buri, Rayong, Chanthaburi and Trat. Minimum temperatures will be 23–26°C and maximum temperatures 33–34°C, with easterly winds of 10–30km/h. Waves will generally remain below one metre but exceed two metres in thunderstorms.
South, east coast: Thunderstorms will cover 70% of the area, with isolated heavy rain in Phetchaburi, Prachuap Khiri Khan, Pattani and Narathiwat, and isolated very heavy rain in Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung and Songkhla. Minimum temperatures will be 23–24°C and maximum temperatures 31–33°C. Winds will be easterly at 15–30km/h from Surat Thani northwards and variable at the same speeds from Nakhon Si Thammarat southwards, while waves will be about one metre and exceed two metres in thunderstorms.
South, west coast: Thunderstorms are expected over 70% of the area, with isolated heavy rain in Ranong, Phang Nga, Phuket and Krabi, and isolated very heavy rain in Trang and Satun. Minimum temperatures will range from 23–24°C and maximum temperatures from 30–33°C, with variable winds of 15–30km/h. Waves will be about one metre, rising above two metres in thunderstorms.
Bangkok and surrounding provinces: Thunderstorms are forecast over 60% of the area. Minimum temperatures will be 25–27°C and maximum temperatures 32–35°C, with easterly winds of 10–20km/h.
Weather updates are available around the clock through the Thai Meteorological Department’s website or by calling 02-399-4012, 02-399-4013 or 1182.
