Meteorological Department Issues 7-Day Weather Forecast; Prepare for Heavy End-of-Month Rainfall and Risk of Flash Floods and Flash Flooding
Thailand's Meteorological Department warns of heavy rainfall and flash flood risks from May 28-31, with the eastern and western-facing southern regions facing the heaviest downpours as monsoon winds strengthen across the country.
The Thai Meteorological Department released a 7-day weather forecast on May 25, 2569 (2026), covering May 25-31, 2569, warning the public to prepare for heavy rainfall at the end of the month and remain vigilant against the dangers of flash floods and flash flooding.
May 25-27, 2569: Rainfall across Thailand is expected to decrease, though heavy showers will continue in isolated areas of the eastern and southern regions due to moderate southwest monsoon winds covering the Andaman Sea, Thailand, and the Gulf of Thailand. The Andaman Sea and upper Gulf of Thailand will see wave heights of 1-2 meters, with heights exceeding 2 meters in thunderstorm areas.
May 28-31, 2569: Rainfall will increase across Thailand with heavy downpours in some areas, particularly in the eastern region and the western-facing southern region, which will experience heavy to very heavy rain in some areas. This is due to a monsoon trough moving across the central region, lower northeastern region, and eastern region, combined with increasingly strong southwest monsoon winds covering the Andaman Sea, Thailand, and the Gulf of Thailand. Wind and wave conditions will strengthen, with wave heights of 2-3 meters in the upper Andaman Sea and exceeding 3 meters in thunderstorm areas. The lower Andaman Sea and upper Gulf of Thailand will experience wave heights of approximately 2 meters, with heights exceeding 2 meters in thunderstorm areas.
Warnings: From May 28-31, residents of the northern, northeastern, central, and eastern-facing southern regions should be alert to heavy rainfall hazards. Residents of the eastern and western-facing southern regions should prepare for very heavy rainfall and accumulated precipitation that may cause sudden flash floods, flooding, and overflowing waterbanks. Mariners in the Andaman Sea and Gulf of Thailand should exercise caution and avoid areas with thunderstorms. Small vessels in the upper Andaman Sea should remain ashore from May 28-31.
Regional Forecasts (May 25-31, 2569):
Northern Region: May 25-28: Thunderstorms in 20-40% of areas May 29-31: Thunderstorms in 40-60% of areas with heavy rain in some places Southwest winds at 10-20 km/hr Low 23-27°C, High 32-38°C
Northeastern Region: May 25-28: Thunderstorms in 10-30% of areas May 29-31: Thunderstorms in 40-60% of areas with heavy rain in some places Southwest winds at 10-20 km/hr Low 23-26°C, High 32-37°C
Central Region: May 25-28: Thunderstorms in 20-40% of areas May 29-31: Thunderstorms in 40-60% of areas with heavy rain in some places Southwest winds at 10-20 km/hr Low 24-27°C, High 32-38°C
Eastern Region: May 25-27: Thunderstorms in 30-40% of areas with heavy rain in some places Southwest winds at 15-35 km/hr, sea waves 1-2 meters high, exceeding 2 meters in thunderstorm areas May 28-31: Thunderstorms in 40-60% of areas with heavy to very heavy rain in some places Southwest winds at 20-35 km/hr, sea waves approximately 2 meters high, exceeding 2 meters in thunderstorm areas Low 25-29°C, High 31-37°C
Southern Region (Eastern Coast): May 26-27: Thunderstorms in 30-40% of areas
