Thailand Weather Alert: Heavy Rains and Rough Seas Expected

The Thai Meteorological Department (TMD) has issued an alert regarding severe weather conditions affecting Thailand as of August 20, 2026. A monsoon trough currently spans the upper North and Northeast regions, connecting to an active low-pressure cell near Hainan, China. Simultaneously, a rather strong southwest monsoon is impacting the Andaman Sea, the Gulf of Thailand, and the mainland.

Residents and travelers should anticipate isolated heavy rains throughout the country, with the potential for very heavy rainfall in the North, Northeast, Central, and Eastern regions. The TMD warns that these conditions may lead to flash floods, overflows, and landslides, particularly in areas near foothills and low-lying waterways.

Maritime conditions are also affected, with waves in the upper Andaman Sea and the upper Gulf expected to reach heights of 2–3 meters, exceeding 3 meters during thundershowers. In the lower Andaman Sea, waves are forecasted at approximately 2 meters, rising above that during storms. All vessels are advised to proceed with caution and avoid areas experiencing thundershowers. Small boats in the upper Andaman Sea and the upper Gulf are specifically instructed to remain ashore. While the TMD has provided these forecasts, the exact duration of these weather patterns and the specific locations most at risk of landslides remain subject to ongoing meteorological updates.