BANGKOK, THAILAND – The Thai Meteorological Department (TMD) has issued a nationwide monsoon alert as a deep monsoon low and the southwest monsoon converge, bringing heavy rain, storms and flash-flood risk to large parts of the country.
Monsoon low brings rain chaos
The monsoon low has settled over the lower central and eastern regions while the southwest monsoon continues to affect the Andaman Sea, the southern provinces and the Gulf of Thailand. This weather pattern will intensify rainfall in several areas, prompting the TMD to warn residents to remain vigilant for localized heavy downpours and sudden flash floods.
Regional outlook
– North: Isolated thunderstorms are expected, especially in Mae Hong Son, Chiang Mai and Tak, with morning temperatures around 22–26°C and daytime highs up to 32–35°C.
– Northeast: Scattered storms will mainly affect provinces such as Chaiyaphum, Nakhon Ratchasima and Buriram. Temperatures should range from 22–25°C overnight to 32–34°C by day.
– Central region: Widespread thunderstorms are forecast, with particularly heavy rain possible in Kanchanaburi, Ayutthaya and Ratchaburi. Morning lows are expected at 22–25°C, rising to 32–34°C during the day.
Bangkok and the south particularly at risk
The Bangkok metropolitan area is forecast to see widespread thunderstorms with isolated heavy downpours. Temperatures will hover between 24–26°C in the early morning and reach 32–34°C by afternoon. The south faces the most severe conditions: the east coast (Chumphon, Surat Thani, Songkhla) is expected to receive intense rain, while the west coast (Phuket, Krabi, Phang Nga) may experience strong storms accompanied by gusty winds.
Coastal and maritime warnings
The TMD has issued explicit cautions for vessels in the Gulf of Thailand and the Andaman Sea: small and medium-sized craft should avoid areas of active thunderstorms and navigate with extreme care. Wave heights could exceed two metres during storm episodes. Eastern coastal provinces such as Rayong, Chanthaburi and Trat can expect winds of 15–30 km/h and hazardous sea conditions.
Duration and outlook
The monsoon conditions are forecast to persist at least through Thursday, with the TMD providing regular updates. While the system could shift or intensify, authorities say a wet and unsettled weekend is likely for much of Thailand.
Official advice and preparedness
Meteorologists urge residents in affected areas to prepare for sudden flooding and to follow local authority instructions. Measures include securing property, avoiding travel through flooded areas, and heeding maritime advisories. Emergency services and local administrations are expected to monitor vulnerable zones and issue targeted warnings as needed.
How to prepare
Individuals should review household emergency plans, keep drainage clear where possible, and stay informed via official TMD bulletins and local announcements. Farmers, transport operators and tourism businesses on the coasts are advised to take contingency steps. Will local communities and vessels be able to weather the surge? Authorities and residents are being tested as the monsoon returns.