Heavy Rain Forecast for Thailand Over Next Seven Days
Thailand faces seven days of heavy rain from August 14-20, with the most intense rainfall expected in northern and northeastern regions as a monsoon trough moves southward, prompting warnings of potential flash floods and rough seas.
The Thai Meteorological Department issued a seven-day weather forecast for August 14-20, 2025. From August 14-17, Thailand will experience isolated heavy rain mainly in the northern, northeastern, and eastern regions due to a monsoon trough passing over northern Thailand, Laos, and northern Vietnam. The southwest monsoon continues to cover the Andaman Sea, Thailand, and the Gulf of Thailand. From August 18-20, rainfall will intensify across the northern and upper northeastern regions with heavy rain in many areas as the monsoon trough shifts southward. Waves in the upper Andaman Sea will remain moderately strong at 2-3 meters during August 14-18, exceeding 3 meters in thunderstorm areas. The upper Gulf of Thailand will see waves around 2 meters, exceeding 2 meters in thunderstorm zones. From August 19-20, waves in both areas will remain 2-3 meters, exceeding 3 meters during thunderstorms. Residents in the northern and upper northeastern regions should beware of heavy rainfall and accumulated water that may cause flash floods, flash flooding, and riverbank overflow, especially in foothill and low-lying areas. Boaters should exercise caution and avoid thunderstorm areas. Small boats in the upper Andaman Sea should remain ashore August 14-16 and 19-20, while small boats in the upper Gulf should stay ashore August 19-20. Regional forecasts: Northern region with 60-80 percent thunderstorm coverage and heavy rain throughout, becoming very heavy August 18-20, southwest winds 10-20 kph, low 23-27°C, high 30-35°C. Northeastern region with 40-60 percent coverage August 14-17, increasing to 60-80 percent August 18-20 with heavy to very heavy rain, southwest winds 10-20 kph, low 23-27°C, high 31-35°C. Central region with 40-60 percent coverage August 14-17, 60-70 percent August 18-20 with heavy rain, southwest winds 10-25 kph, low 23-28°C, high 30-36°C. Eastern region with 60-70 percent coverage and heavy rain throughout, southwest winds 20-35 kph August 14-18 with 2-meter waves (exceeding 2 meters in thunderstorms), and 20-40 kph winds August 19-20 with 2-3 meter waves (exceeding 3 meters in thunderstorms), low 23-28°C.
