Thailand faces heavy rain and flood risk until September 13
Bangkok and surrounding provinces are among areas urged to watch for flash floods as the monsoon shifts and strengthens across Thailand
Thailand will face heavier rainfall from September 8–13, 2026, with widespread heavy rain and isolated very heavy downpours beginning in the Northeast before affecting other regions, the Thai Meteorological Department (TMD) has warned.
Its third advisory, numbered 193/2569 and issued at 5am on Tuesday (September 8), urged residents to prepare for flash floods and rapid run-off caused by intense downpours and accumulated rainfall.
The department highlighted September 9–11 as a period requiring particular caution in the lower Northeast, the Central region including Bangkok and surrounding provinces, the East and the upper South.
People living near foothills, waterways and low-lying areas should remain alert. The warning follows the department’s earlier forecast of increasing rain during September 8–13.
Rainfall to shift southwards
A monsoon trough will lie across the North, upper Central region and Northeast during September 8–11. Combined with a moderate southwest monsoon over the Andaman Sea, Thailand and the Gulf of Thailand, it will bring heavy rain to many parts of upper Thailand, with very heavy falls in some locations.
Conditions will change during September 12–13, when a high-pressure system, or cool air mass, from China extends over the upper North and upper Northeast.
This will push the monsoon trough southwards across the lower Central region and the East, extending into a strong low-pressure area over the central South China Sea.
The southwest monsoon over the Andaman Sea, the South and the Gulf of Thailand will also strengthen. Rainfall is expected to ease in the North and Northeast but increase in the Central region, including Bangkok and surrounding provinces, the East and the South, with heavy to very heavy rain in some areas.
Flood precautions and possible storm development
Residents should avoid travelling along routes repeatedly affected by flooding, particularly low-lying roads where water could temporarily accumulate. The department also advised people to plan daily activities and journeys carefully to reduce potential disruption and danger.
Separately, a low-pressure area near the Philippines could strengthen into a tropical cyclone during September 11–13 and move into the central South China Sea, the department said.
The public should monitor further TMD announcements. Updates are available through the department’s website and its round-the-clock telephone services on 02-399-4012–13 and 1182.
The next advisory is scheduled for 5pm on September 8.
