TMD issues fresh warning for heavy to very heavy rain across parts of Thailand on October 18–25
Thailand’s South and East face heavy rain first, with risks spreading to Bangkok and other regions from October 21 as TMD warns of flash floods.
- The Thai Meteorological Department has issued a warning for heavy to very heavy rain across parts of Thailand from October 18–25, with risks of flash floods, run-off, and landslides.
- The severe weather will first impact the South and East (Oct 18–20), before rainfall increases in the lower Northeast, Central region, Bangkok, and upper South from October 21–25.
- Bangkok and surrounding provinces are specifically forecast to face heavy rain and a risk of flooding between October 21–24.
- The warning also includes a caution for mariners, as thunderstorms could cause waves to exceed three metres in the Andaman Sea and Gulf of Thailand.
The Thai Meteorological Department (TMD) issued a fresh warning on October 17, 2026, for heavy to very heavy rain across parts of Thailand during October 18–25, with accumulated rainfall raising the risk of flash floods, rapid run-off and landslides. Warning No 1 (260/2026) was issued at 5am. The eight-day outlook covers a new spell of unsettled weather during the transition from the rainy season towards the cool season.
The TMD urged residents near foothills, waterways and low-lying areas to prepare for heavy rainfall and gusty winds. Travellers should avoid routes prone to repeated flooding, particularly low-lying roads where water could accumulate temporarily.
South and East face first phase of heavy rain
The TMD forecasts persistent rain in the South and East on October 18–20, with heavy to very heavy falls in some areas.
From October 21–25, the TMD expects rainfall to increase across the lower Northeast, Central region, Bangkok and surrounding provinces, the East and upper South. Some areas could experience heavy to very heavy rain and gusty winds.
A monsoon trough will initially lie across the lower South, while the southwest monsoon affects the lower Andaman Sea, according to the TMD.
The TMD expects the trough to move northwards across the upper South, upper Gulf of Thailand and East. Meanwhile, a high-pressure system, or cool air mass, from China will extend over the upper North, upper Northeast and South China Sea.
Bangkok faces flooding risk on October 21–24
Bangkok and surrounding provinces are forecast to experience heavy rain on October 21–24, with rainfall of 35.1–65mm over 24-hour periods in affected areas.
Low-lying neighbourhoods, locations with recurring flooding and areas with insufficient drainage capacity could experience temporary standing water. Flooding could also disrupt traffic during rush hours.
The forecast does not mean heavy rain will affect every location in Bangkok and surrounding provinces. Residents should monitor live rain radar alongside updated forecasts when planning journeys.
Daily forecast identifies provinces at risk
The TMD’s daily outlook identifies the following areas for heavy or very heavy rainfall. The locations and severity vary throughout the eight-day period.
- October 18 — Heavy rain: Southern provinces of Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala, Narathiwat, Ranong, Phang Nga, Phuket, Krabi, Trang and Satun.
- October 19 — Heavy rain: Southern provinces of Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Yala, Narathiwat, Ranong, Phang Nga, Phuket, Krabi, Trang and Satun.
- October 20 — Heavy rain: In the East, Chonburi, Rayong, Chanthaburi and Trat; in the South, Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Ranong and Phang Nga.
- October 21 — Very heavy rain: Chonburi, Rayong and Chanthaburi in the East, and Phetchaburi in the South. Heavy rain: In the Northeast, Nakhon Ratchasima, Buriram and Ubon Ratchathani; in the Central region, Suphanburi, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Sakhon and Samut Songkhram, together with Bangkok and surrounding provinces; in the East, Nakhon Nayok, Prachinburi, Chachoengsao and Trat; and in the South, Prachuap Khiri Khan.
- October 22 — Very heavy rain: Chonburi and Rayong in the East. Heavy rain: Samut Songkhram, Bangkok and surrounding provinces in the Central region; Chachoengsao, Chanthaburi and Trat in the East; and Phetchaburi in the South.
- October 23 — Heavy rain: In the Central region, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Sakhon and Samut Songkhram, together with Bangkok and surrounding provinces; in the East, Chachoengsao, Chonburi and Rayong; and in the South, Phetchaburi, Prachuap Khiri Khan, Chumphon, Ranong, Phang Nga and Phuket.
- October 24 — Very heavy rain: Phang Nga, Phuket and Krabi in the South. Heavy rain: Samut Sakhon, Bangkok and surrounding provinces in the Central region; Chonburi and Rayong in the East; and Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Nakhon Si Thammarat, Ranong and Trang in the South.
- October 25 — Very heavy rain: Phetchaburi, Prachuap Khiri Khan, Ranong, Phang Nga and Phuket in the South. Heavy rain: Ratchaburi, Samut Sakhon and Samut Songkhram in the Central region; and Surat Thani, Songkhla and Krabi in the South.
Thunderstorms could bring waves above three metres
The TMD warned that waves in the Andaman Sea and Gulf of Thailand could exceed three metres in areas experiencing thunderstorms. Mariners should proceed cautiously and avoid sailing through storms.
The TMD urged the public to plan daily activities and travel carefully and follow its announcements. Weather information is available through the department’s website and around the clock on 1182, 02-399-4012 and 02-399-4013.
The TMD’s next warning bulletin is scheduled for 5pm on October 17.
