Thailand Braces for Heavy Rain and Flash Floods Through Mid-September
Thailand's meteorological department warns of heavy to very heavy rainfall from September 8-13, with risks of flash floods and landslides across the country as a monsoon trough and southwest monsoon converge.
The Thai Meteorological Department issued alert number one warning of heavy to very heavy rainfall across Thailand with effects from September 8-13, 2026. During September 8-11, a monsoon trough will pass through the northern, upper central, and northeastern regions, combined with a moderate-strength southwest monsoon over the Andaman Sea, Thailand, and the Gulf of Thailand. This will bring heavy rain to many areas in upper Thailand, with very heavy falls in some locations, starting first in the northeastern region before affecting other areas.
From September 12-13, a high-pressure system from China will move southward, pushing the monsoon trough toward the lower central and eastern regions. The southwest monsoon over the Andaman Sea, southern region, and Gulf of Thailand will strengthen. Rainfall is expected to decrease in the north and northeastern regions, while the central region, Bangkok and its vicinity, eastern region, and southern region will see increased rainfall with heavy to very heavy falls in some areas.
The public is warned to be cautious of hazards from heavy rainfall, which may cause flash floods and landslides, particularly in foothill areas, low-lying zones, and near waterways. Travel through flood-prone areas should be avoided, especially in depression zones where water can accumulate rapidly. Additionally, a low-pressure system near the Philippines is expected to intensify into a tropical cyclone between September 11-13 and move toward the central South China Sea. The Meteorological Department will issue its next alert on September 7 at 5 p.m., and the public is advised to monitor updates at tmd.go.th or by calling 0-2399-4012-13 and 1182 available 24 hours daily.
