Heavy Rain Warning Issued for Northern Thailand August 18-21
Northern Thailand faces a fourth heavy rain warning from August 18-21, with 24 provinces at risk of flash flooding and landslides as a monsoon trough combines with strong southwestern winds across the region.
On August 17, the Meteorological Department issued its fourth warning regarding heavy to very heavy rain across upper Thailand between August 18-21, 2025. The northern and northeastern regions will be most affected due to a monsoon trough passing through those areas combined with the southwestern monsoon system covering the Andaman Sea, Thailand, and the Gulf of Thailand, which will bring relatively strong winds.
The public is urged to be cautious of heavy rainfall and accumulated water that may cause flash flooding and landslides, particularly in sloped areas near waterways and low-lying terrain. Travel should be avoided on routes prone to repeated flooding, especially in low-lying areas where water may accumulate quickly.
Currently, the department has identified 24 provinces facing heavy rain warnings. Waves in the upper Andaman Sea are expected to reach 2-3 meters between August 19-21, with heights exceeding 3 meters in thunderstorm areas. The lower Andaman Sea and upper Gulf of Thailand will see waves around 2 meters, exceeding 2 meters during storms.
Fishermen in the Andaman Sea and Gulf of Thailand are advised to navigate carefully and avoid thunderstorm zones. Small vessels in the upper Andaman Sea should avoid departing shore during this period. The public is encouraged to plan activities and travel carefully and monitor updates from the Meteorological Department at www.tmd.go.th or by calling 0-2399-4012-13 and 1182, available 24 hours daily. The next warning will be issued on August 17 at 5 p.m.
