Heavy rain raises flood risk in Bangkok and eastern Thailand
The Thai Meteorological Department warns of very heavy rain in two eastern provinces, flash floods and waves above 3 metres in thundery areas of the upper Andaman Sea.
- Thailand's Meteorological Department has issued a warning for heavy to very heavy rain in Bangkok, its vicinity, and eastern Thailand.
- The severe weather is caused by a monsoon trough combined with a high-pressure system, creating a significant risk of flash floods and forest run-off.
- Residents in affected regions, particularly in low-lying areas, have been advised to be cautious of accumulated rainfall and avoid travel on flood-prone routes.
The Thai Meteorological Department (TMD) issued a warning at 5pm on Sunday (September 20, 2026) over heavy to very heavy rain in Thailand and strong winds and waves in the Andaman Sea.
The warning remained in effect through Sunday.
Heavy rain warning covers lower central Thailand, Bangkok and vicinity, and eastern Thailand
Thailand continued to experience heavy rain in some areas on Sunday.
A high-pressure area or cool air mass from China covered the upper parts of northern and northeastern Thailand, while a monsoon trough lay across lower central, eastern and upper southern Thailand.
A fairly strong south-westerly monsoon also prevailed over the Andaman Sea, southern Thailand and the Gulf of Thailand.
Heavy rain could continue, particularly in lower central Thailand, including Bangkok and its vicinity, and eastern Thailand.
People across Thailand were advised to beware of heavy and accumulated rainfall, which could cause flash floods and forest run-off, particularly in foothill areas near waterways and in low-lying areas.
They were also advised to avoid travelling on routes prone to recurrent flooding, especially in low-lying areas where short-term flooding could occur.
Small boats advised to stay ashore amid high waves
Winds and waves in the upper Andaman Sea remained fairly strong, with waves of 2-3 metres and more than 3 metres in thundery areas.
Mariners in the Gulf of Thailand and the Andaman Sea were advised to proceed with caution and avoid sailing in areas with thunderstorms.
Small boats in the upper Andaman Sea were advised to stay ashore through Sunday.
To ensure safety and reduce possible impacts, people were advised to plan their daily activities and journeys carefully during this period and follow TMD announcements.
Information was available around the clock through the department’s website or by calling 0-2399-4012-13 or 1182.
The department said this would be the final warning concerning this weather event.
Areas at risk from heavy to very heavy rain
Provinces expected to be affected by very heavy rain
- East: Nakhon Nayok and Prachin Buri
Provinces expected to be affected by heavy rain
- North: Sukhothai, Tak, Kamphaeng Phet, Phitsanulok and Phetchabun
- Northeast: Loei, Chaiyaphum, Khon Kaen, Amnat Charoen, Nakhon Ratchasima, Buri Ram, Surin, Si Sa Ket and Ubon Ratchathani
- Central region: Nakhon Sawan, Uthai Thani, Lopburi, Saraburi, Suphan Buri, Phra Nakhon Si Ayutthaya, Kanchanaburi, Ratchaburi and Nakhon Pathom, as well as Bangkok and its vicinity
- East: Sa Kaeo, Chachoengsao, Chonburi, Rayong, Chanthaburi and Trat
- South: Phetchaburi, Prachuap Khiri Khan, Chumphon, Phatthalung, Songkhla, Pattani, Yala, Narathiwat, Ranong, Phang Nga, Phuket, Krabi, Trang and Satun
