Heavy Rain Expected July 20-21, Flood Risk Nationwide
Heavy rain and potential flooding threaten Thailand on July 20-21 as a low-pressure system moves over Laos and northern Vietnam, with the northern and western central regions most at risk.
Thailand's Meteorological Department has issued a seven-day regional weather forecast covering July 15-21, 2025. From July 16-19, rainfall is expected to decrease overall, though heavy showers will persist in the northern and upper northeastern regions due to a low-pressure system over northern Vietnam, while the southwest monsoon weakens over the Andaman Sea and Thailand. Waves in the Andaman Sea and Gulf of Thailand are expected to be 1-2 meters high, with thunderstorm areas seeing waves above 2 meters.
From July 20-21, rainfall is forecast to increase significantly with heavy downpours particularly in the northern region and western central areas as the low-pressure system shifts over Laos and northern Vietnam and the southwest monsoon strengthens. Wave heights remain moderate at 1-2 meters, with thunderstorm areas again experiencing waves exceeding 2 meters.
Public Warning: During July 20-21, residents in northern Thailand and the western central region should be alert to dangers from heavy and accumulated rainfall, which may cause flash flooding, flash floods, and riverbank overflows, especially in foothill areas near waterways and low-lying zones.
Regional Forecast (July 15-21, 2025):
Northern Region: July 15-19 will see thunderstorms in 30-40% of the area with some heavy showers; southwest winds 10-15 km/h; low 23-27°C, high 29-35°C. July 20-21 will have thunderstorms in 40-60% of the area with some heavy showers; southwest winds 10-20 km/h.
Northeastern Region: July 15-17 will have thunderstorms in 30-40% of the area with some heavy showers; southwest winds 10-20 km/h. July 18-21 will see thunderstorms in 20-30% of the area, with heavy showers in the upper northeast on July 21; southwest winds 10-20 km/h; low 24-26°C, high 29-35°C.
Central Region: July 16-20 will have thunderstorms in 20-40% of the area; southwest winds 10-20 km/h. July 21 will see thunderstorms in 30-40% of the area with some heavy showers in the western central zone; southwest winds 10-25 km/h; low 24-27°C, high 30-36°C.
Eastern Region: July 16-17 and 21 will have thunderstorms in 30-40% of the area; July 18-20 will see thunderstorms in 20-30% of the area; southwest winds 15-35 km/h; sea waves 1-2 meters, exceeding 2 meters in thunderstorm areas; low 24-28°C, high 30-35°C.
Southern Region (East Coast): July 16-19 will feature thunderstorms.
