"Meteorological Department" is the official weather agency of Thailand. It issues weather forecasts and warnings. It has warned that during 12-18 August, some areas in Thailand will still experience heavy rainfall, which may cause flash floods and landslides.
Date: 12 August 2026 GMT+7Meteorological DepartmentThe 24-hour weather forecast states that the northern, northeastern, central, and eastern regions will continue to experience heavy rainfall in some areas due to a monsoon trough passing through upper northern Thailand, upper Laos, and upper northeastern Thailand. Meanwhile, the southwest monsoon covering the Andaman Sea, Thailand, and the Gulf of Thailand is relatively strong. Residents in these areas should be cautious of heavy and accumulated rainfall that may trigger flash floods and landslides, especially in foothill areas near waterways and low-lying plains.
Regarding sea conditions, the upper Andaman Sea and upper Gulf of Thailand will experience relatively strong winds with waves 2-3 meters high, and over 3 meters in areas with thunderstorms. Mariners are advised to navigate carefully and avoid areas with thunderstorms. Small boats in these regions should refrain from leaving shore.
The 7-day weather forecast from 12 to 18 August 2026 indicates that Thailand will still have heavy rain in some parts of the north, northeast, central, east, and western south. This is due to a monsoon trough crossing the upper north and upper northeast into a low-pressure area over northern Vietnam, combined with a relatively strong southwest monsoon covering the Andaman Sea, Thailand, and the Gulf of Thailand.
During 12-18 August 2026, the upper Andaman Sea will continue to experience relatively strong winds with waves 2-3 meters high, exceeding 3 meters in thunderstorms. The upper Gulf of Thailand will have waves about 2 meters high. The lower Andaman Sea and lower Gulf of Thailand will have waves 1-2 meters high, exceeding 2 meters in thunderstorms.
Precautionary advice: Residents in Thailand should be alert to dangers from heavy and accumulated rainfall that may cause flash floods, landslides, and river overflows, especially in foothill areas near waterways and lowlands. Mariners in the Gulf of Thailand and Andaman Sea should navigate cautiously and avoid areas with thunderstorms throughout this period. Small boats in the upper Andaman Sea should avoid leaving shore between 12 and 18 August 2026 for safety.