Bangkok underwater: Severe monsoon flooding in Thailand
In late September 2026, Bangkok experienced one of its most severe flood events in recent years after an exceptionally intense period of monsoon rainfall linked to a low-pressure weather system affecting mainland Southeast Asia. More than 300mm of rain fell over a two to three-day period, overwhelming Bangkok's drainage and canal systems, causing widespread surface water flooding across the low-lying metropolitan area. This flood mechanism differs from the major 2011 Thailand floods, which were largely driven by prolonged river flooding.
The floods inundated neighbourhoods across Bangkok as well as surrounding provinces, with fatalities reported and hundreds of thousands of households experiencing property damage or displacement. Economic losses have been estimated at over US$300 million, reflecting damage to homes, businesses, infrastructure, manufacturing supply chains and the tourism sector. The event has highlighted Bangkok's vulnerability to short-duration extreme rainfall events.
JBA has produced an indicative footprint for the event, based on its stochastic Global Flood Event Set. Download it via our Client Portal or request a copy by emailing eventresponse@jbarisk.com.
We will update the footprint and this report with further information about the event in the coming days.
