TMD warns of heavy rain, 2–3m waves on September 24–27
Bangkok and other Thai regions face flood risks until September 27, while small boats in the upper Gulf and upper Andaman Sea should stay ashore.
The Thai Meteorological Department (TMD) issued a warning at 5pm Thai time on September 24, 2026 for heavy to very heavy rain across parts of Thailand through September 27. Bangkok and surrounding provinces are among the areas facing flood risks from the downpours.
The TMD’s advisory No.7 (223/2026), signed by director-general Sugunyanee Yavinchan, forecasts heavy rain in many areas and very heavy rain in some locations across the North, lower Northeast, Central region, East and South.
Low-pressure system raises rain risks across Thailand
A strong low-pressure system over Cambodia is expected to move across the lower Northeast, East and Central region, including Bangkok and surrounding provinces, along a monsoon trough over upper Thailand, according to the TMD. The south-west monsoon over the Andaman Sea, southern Thailand and the Gulf of Thailand is also strengthening.
The TMD warned that heavy downpours and accumulated rainfall could trigger flash floods, overflowing waterways and landslides, particularly near foothills, along waterways and in low-lying areas.
Travellers should avoid routes prone to repeated flooding, especially low-lying roads where short-term flooding may occur, the TMD advised.
Small boats in upper Gulf and upper Andaman Sea advised to stay ashore
The TMD advised small boats in the upper Gulf of Thailand and upper Andaman Sea to remain ashore through September 27 as stronger winds increase wave heights. All vessels in the Gulf and Andaman Sea should navigate cautiously and avoid thunderstorms.
The TMD’s wave forecast for September 24–27 distinguishes between the upper and lower waters:
- Upper Gulf of Thailand and upper Andaman Sea: Waves of 2–3 metres, exceeding 3 metres during thunderstorms.
- Lower Gulf of Thailand and lower Andaman Sea: Waves of around 2 metres, exceeding 2 metres during thunderstorms.
TMD identifies daily heavy-rain risk areas
The TMD’s daily outlook places Bangkok and surrounding provinces in the very-heavy-rain category on all four days. The provincial forecasts distinguish between heavy and very heavy rainfall as follows.
September 24, 2026
Very heavy rain
- Northeast: Nakhon Ratchasima and Buri Ram.
- Central region: Saraburi, Ang Thong, Phra Nakhon Si Ayutthaya, Nakhon Pathom and Samut Sakhon, together with Bangkok and surrounding provinces.
- East: Nakhon Nayok, Prachin Buri, Sa Kaeo, Chachoengsao, Chonburi, Rayong, Chanthaburi and Trat.
Heavy rain
- North: Sukhothai, Tak, Kamphaeng Phet, Phitsanulok, Phichit and Phetchabun.
- Northeast: Loei, Nong Bua Lam Phu, Chaiyaphum, Khon Kaen, Maha Sarakham, Surin, Si Sa Ket and Ubon Ratchathani.
- Central region: Nakhon Sawan, Uthai Thani, Chai Nat, Sing Buri, Lop Buri, Suphan Buri, Kanchanaburi, Ratchaburi and Samut Songkhram.
- South: Phetchaburi, Prachuap Khiri Khan, Chumphon and Surat Thani.
September 25, 2026
Very heavy rain
- North: Phetchabun.
- Northeast: Nakhon Ratchasima.
- Central region: Nakhon Sawan, Chai Nat, Sing Buri, Ang Thong, Lop Buri, Saraburi, Phra Nakhon Si Ayutthaya, Suphan Buri and Kanchanaburi, together with Bangkok and surrounding provinces.
- East: Nakhon Nayok, Prachin Buri, Sa Kaeo, Chachoengsao, Chonburi, Rayong, Chanthaburi and Trat.
Heavy rain
- North: Mae Hong Son, Chiang Mai, Lamphun, Lampang, Uttaradit, Sukhothai, Tak, Kamphaeng Phet, Phitsanulok and Phichit.
- Northeast: Loei, Nong Bua Lam Phu, Chaiyaphum, Khon Kaen, Kalasin, Maha Sarakham, Roi Et, Buri Ram, Surin and Si Sa Ket.
- Central region: Uthai Thani, Ratchaburi, Nakhon Pathom, Samut Sakhon and Samut Songkhram.
- South: Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Ranong and Phang Nga.
September 26, 2026
Very heavy rain
- North: Tak and Phetchabun.
- Central region: Nakhon Sawan, Uthai Thani, Saraburi, Phra Nakhon Si Ayutthaya, Suphan Buri, Kanchanaburi, Ratchaburi and Nakhon Pathom, together with Bangkok and surrounding provinces.
- East: Nakhon Nayok, Prachin Buri, Chonburi, Rayong, Chanthaburi and Trat.
Heavy rain
- North: Mae Hong Son, Chiang Mai, Sukhothai, Uttaradit, Kamphaeng Phet, Phitsanulok and Phichit.
- Northeast: Chaiyaphum, Khon Kaen, Nakhon Ratchasima and Buri Ram.
- Central region: Chai Nat, Lop Buri, Sing Buri, Ang Thong, Samut Sakhon and Samut Songkhram.
- East: Sa Kaeo and Chachoengsao.
- South: Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Phang Nga and Phuket.
September 27, 2026
Very heavy rain
- North: Tak and Kamphaeng Phet.
- Central region: Nakhon Sawan, Uthai Thani, Suphan Buri, Kanchanaburi and Ratchaburi, together with Bangkok and surrounding provinces.
- East: Nakhon Nayok, Prachin Buri, Chanthaburi and Trat.
Heavy rain
- North: Sukhothai, Phitsanulok, Phichit and Phetchabun.
- Northeast: Chaiyaphum, Khon Kaen, Nakhon Ratchasima and Buri Ram.
- Central region: Chai Nat, Lop Buri, Saraburi, Sing Buri, Ang Thong, Phra Nakhon Si Ayutthaya, Nakhon Pathom, Samut Sakhon and Samut Songkhram.
- East: Sa Kaeo, Chachoengsao, Chonburi and Rayong.
- South: Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Phang Nga and Phuket.
TMD schedules next advisory for 5am on September 25
The TMD plans to issue its next advisory at 5am Thai time on September 25, 2026.
The TMD urged the public to plan daily activities and journeys carefully and follow further announcements. Weather information is available around the clock through the department’s website or by calling 02-399-4012, 02-399-4013 or 1182.
