TMD issues heavy rain warning for 46 provinces and Greater Bangkok

The Thai Meteorological Department (TMD) announced on Sunday (September 20, 2026), warning of heavy to very heavy rain in Thailand and strong winds and waves in the Andaman Sea, with the warning in effect through the same day.

Heavy rain continued in some areas because a high-pressure system or cold air mass from China covered the upper North and upper Northeast.

At the same time, a monsoon trough extended across the lower Central region, the East and the upper South, while a moderately strong southwest monsoon prevailed over the Andaman Sea, the South and the Gulf of Thailand.

Provinces expected to be affected by heavy rain

• North: Uttaradit, Sukhothai, Tak, Kamphaeng Phet, Phitsanulok, Phichit and Phetchabun.
• Northeast: Loei, Nong Bua Lamphu, Chaiyaphum, Khon Kaen, Maha Sarakham, Amnat Charoen, Nakhon Ratchasima, Buriram, Surin, Sisaket and Ubon Ratchathani.
• Central: Nakhon Sawan, Uthai Thani, Lopburi, Saraburi, Suphan Buri, Phra Nakhon Si Ayutthaya, Kanchanaburi, Ratchaburi and Nakhon Pathom, as well as Bangkok and the surrounding metropolitan region.
• East: Nakhon Nayok, Prachinburi, Sa Kaeo, Chachoengsao, Chonburi, Rayong, Chanthaburi and Trat.
• South: Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, Ranong, Phang Nga, Phuket, Krabi and Trang.

People across Thailand were advised to beware of hazards from heavy and accumulated rainfall, which could cause flash floods and run-off from forested areas, particularly on foothill slopes near waterways and in low-lying areas. They should avoid travelling on routes prone to repeated flooding, particularly in low-lying areas where short-term flooding could occur.

Winds and waves in the upper Andaman Sea were moderately strong, with waves reaching 2-3 metres and exceeding 3 metres in areas with thundershowers.

Mariners in the Gulf of Thailand and the Andaman Sea were advised to navigate with caution and avoid areas with thundershowers. Small boats in the upper Andaman Sea should remain ashore for one more day.

For safety and to reduce possible impacts, people were urged to plan their daily activities and travel carefully during this period.

The public was also asked to monitor TMD announcements. Information was available at http://www.tmd.go.th or by calling 0-2399-4012-13 or 1182, 24 hours a day.