Thailand Braces for Heavy Rain Through August 21
Thailand's Meteorological Department warned of heavy to very heavy rainfall across the north and northeast through August 21, with monsoon winds threatening flash floods in hilly areas and dangerous 2-3 meter waves across the Andaman Sea.
The Meteorological Department issued its sixth warning on August 18, 2025, alerting northern and northeastern Thailand to heavy to very heavy rainfall from August 18-21. A monsoon trough passing over the north and upper northeast, combined with strong southwest winds over the Andaman Sea, will bring intense precipitation and cumulative rainfall that could trigger flash floods and flash flooding, particularly in hilly areas near waterways and low-lying zones. Residents are urged to avoid repeatedly flooded routes and exercise caution during travel, especially in basin areas where water may collect rapidly.
Wave heights in the upper Andaman Sea will reach 2-3 meters from August 19-21, with thunderstorm areas seeing waves above 3 meters. The lower Andaman Sea and upper Gulf of Thailand will see approximately 2-meter waves, exceeding 2 meters in areas with thunderstorms. Fishermen are advised to navigate with care, avoid thunderstorm zones, and small boats in the upper Andaman Sea should remain ashore during this period.
The public is urged to plan activities and travel carefully, monitor the Meteorological Department website at tmd.go.th or call 0-2399-4012-13 and 1182 for updates available 24 hours daily. The next warning will be issued on August 18 at 5 p.m.
