Upper Thailand faces very heavy rain and floods on October 4–7
Thailand faces thunderstorms, strong gusts and flood risks from October 4–7, with Bangkok among areas affected during the wet spell
- The Thai Meteorological Department (TMD) is warning of very heavy rain, thunderstorms, and strong gusts in parts of Thailand from October 4 to 7.
- The severe weather is caused by a cool air mass from China meeting the south-west monsoon, creating a risk of flash floods and run-off.
- The affected areas will shift, starting in the North and Northeast on Oct 4, expanding to the Central region (including Bangkok) and East on Oct 5-6, and then moving to the South by Oct 7.
- Mariners are advised to navigate with caution as waves in the Andaman Sea and Gulf of Thailand could exceed 2 meters during thunderstorms.
The Thai Meteorological Department (TMD) issued its second advisory at 5am on Friday (October 2, 2026), warning that unsettled weather will bring thunderstorms, strong gusts and isolated heavy to very heavy rain to parts of Thailand from October 4–7. The conditions could trigger flash floods and run-off, particularly on foothill slopes near waterways and in low-lying areas, where accumulated rainfall could also cause flooding.
The latest advisory, No. 2 (236/2026), updates an earlier warning about unsettled weather expected during the final stages of the rainy season. A previous TMD forecast had already indicated that Bangkok could face heavy rain and gusty winds during the October 4–7 period.
North and Northeast face unsettled weather first on October 4
The TMD forecast that the first phase of the unsettled weather on October 4 would affect the upper and eastern parts of the North as well as the Northeast.
On October 5–6, the affected area is expected to expand across the North, Central region, including Bangkok and surrounding provinces, the East and upper South. Rainfall in the Northeast is forecast to decrease during this period.
By October 7, the main areas affected are expected to shift to the western parts of the North and Central region, as well as the South, while rainfall is forecast to ease elsewhere.
Chinese cold air meets south-west monsoon
The TMD attributed the changing conditions to a high-pressure system, or cool air mass, from China extending over the North and upper Northeast during the closing stages of Thailand's rainy season.
The arrival of the cooler air is expected initially to trigger thunderstorms, while the south-west monsoon will continue to prevail over the Andaman Sea, the South and the Gulf of Thailand.
The TMD urged people to beware of thunderstorms, strong gusts and heavy or accumulated rainfall that could cause flash floods and run-off. Particular caution is advised on foothill slopes near waterways and in low-lying areas vulnerable to flooding.
People should also avoid open areas, large trees and unsecured billboards during thunderstorms and strong winds.
Waves could exceed 2 metres during thunderstorms
Winds and waves in the Andaman Sea and Gulf of Thailand are expected to strengthen, with waves exceeding 2 metres in areas affected by thunderstorms.
The TMD advised mariners in both seas to check their routes, navigate cautiously and avoid sailing in thunderstorm areas.
Rain is expected to persist in the East and South from October 8–12, with isolated heavy to very heavy downpours forecast in some areas.
The TMD urged the public to follow weather forecasts closely and plan daily activities and travel carefully during the affected periods. Weather updates are available around the clock through the Thai Meteorological Department website and its hotlines at 02-399-4012, 02-399-4013 and 1182.
The second advisory was issued at 5am on October 2, with the TMD scheduled to issue its next advisory at 5pm the same day.
