Bangkok and seven neighbouring provinces have been warned to prepare for possible riverside flooding during a six-day high-tide period from September 29 to October 4, 2026.

The Office of the National Water Resources (ONWR) said high tides, water flowing downstream from upper river basins and a fairly strong south-west monsoon could combine to push up river levels.

The warning covers Chachoengsao, Samut Prakan, Bangkok, Nonthaburi, Pathum Thani, Samut Sakhon, Nakhon Pathom and Samut Songkhram.

Four river systems under watch

ONWR identified areas beside the Bang Pakong, Chao Phraya, Tha Chin and Mae Klong rivers as being particularly exposed during the high-tide period.

Floodwater moving down from upstream areas is expected to add to water volumes further downstream. This could raise river levels enough to inundate nearby riverside communities, especially where permanent flood protection is absent.

The south-west monsoon remains fairly strong over the Andaman Sea, southern Thailand and the Gulf of Thailand, ONWR said. It is also strengthening winds and waves.

Communities outside flood embankments, as well as those without permanent flood defences, have been asked to take particular care.

Three major roads may be affected

Sections of Sukhumvit Road, Suksawat Road and Rama II Road could also be affected by rising water or river overflow, according to the warning.

Relevant agencies in all eight provinces have been told to closely monitor conditions and prepare response measures during the six-day period.

Residents in low-lying areas and those living near rivers should follow water-level updates, move valuables and belongings to higher ground where necessary, and plan journeys in advance.

Picture courtesy of The Nation

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29 September 2026

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Yup, Madam has ordered our sandbags. We have the bags, sand is coming later today.

We didn't have a problem with the big rain (the cats were not impressed), now it's arriving from up-north.

Fairly live coverage here:

Also, wasn't there a warning yesterday that the Chao Phaya Dam was releasing excess water? I guess that will add to this.

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Well, we have had the prelude; now we get ready for the main event. This is where we shall see if the government actions over the past few years are effective

Bangkok is doomed anyway. It will be mostly underwater all year round by 2050.

There is only one thing that can save the city and I don't hear anything about that plan.