BANGKOK, THAILAND – The Meteorological Department has issued a monsoon warning as an active trough and strong southwesterly monsoon are set to bring heavy storms across large parts of the country over the next 24 hours.
Overview
The system is centered over the lower central region and is affecting the East and upper South, while a vigorous southwesterly monsoon prevails over the Andaman Sea, the lower South and the Gulf of Thailand. Bangkok and surrounding provinces face a 70% chance of thunderstorms, with torrential rain possible in some areas. Temperatures are forecast to range from about 24°C at night to 35°C by day amid variable winds.
Monsoon trough and expected impacts
The active monsoon trough is driving widespread convective activity. Forecasters warn of short-duration, high-intensity downpours that can quickly reduce visibility, overwhelm drains and trigger flash floods. The heavy rain is expected to persist through Monday morning.
East: heightened risk in coastal provinces
The eastern provinces—including Chonburi, Rayong and Trat—are particularly vulnerable, with about 70% of the area forecast to experience thunderstorms and heavy rain. Maritime authorities have issued advisories for seafarers: wave heights may exceed two metres in affected thunderstorm zones.
South: widespread warnings along both coasts
The South remains under storm alert. On the Gulf (east) coast, Prachuap Khiri Khan, Songkhla and the southern border provinces are among the most affected. On the Andaman (west) coast, Trang and Satun should prepare for severe thunderstorms. The strong southwesterly monsoon will produce rough seas and hazardous conditions for small and medium-sized vessels.
West, North and Northeast: variable exposure
The western provinces around Kanchanaburi and Ratchaburi face an estimated 60% thunderstorm likelihood. Northern provinces see a lower probability overall—around 20%—but Tak and Phitsanulok are expected to experience localized storms. In the northeast, Khon Kaen, Nakhon Ratchasima and Ubon Ratchathani have an estimated 40% chance of thunderstorms.
Advice for residents and visitors
Authorities urge residents in low-lying and flood-prone areas to stay alert and prepare for sudden flooding and flash flows. Motorists should avoid flooded roads, expect traffic disruptions and possible power outages, and follow instructions from local emergency services. Mariners and fishermen are advised to exercise extreme caution or avoid going to sea while conditions remain dangerous.
Ongoing coverage and public input
The Meteorological Department will continue to monitor and update forecasts. Officials recommend taking precautionary measures now rather than waiting. Have you experienced flooding, traffic chaos or power cuts during the recent monsoon activity? Share your observations—they help build a clearer picture of the storm’s local impacts.