The Meteorological Department has issued its 5th warning for heavy to very heavy rain. This is due to a monsoon trough passing through the upper northern and upper northeastern regions.
On 6 August 2026, the Meteorological Department announced the following: Strong winds and waves are expected in the upper Andaman Sea and upper Gulf of Thailand, along with heavy to very heavy rain across Thailand (impact expected from 6 to 9 August 2026), as stated in the 5th bulletin. It stated that the northern, northeastern, and eastern regions will see increasing rainfall, with some areas experiencing heavy to very heavy rain. The central region, including Bangkok and its vicinity, and the southern region will have heavy rain in some areas. This is due to the monsoon trough crossing the upper northern and upper northeastern regions combined with a strong southwest monsoon covering the Andaman Sea, Thailand, and the Gulf of Thailand. People are advised to beware of dangers from heavy to very heavy rain and accumulated rainfall that may cause flash floods and mountain stream flash floods, especially in foothill areas near waterways and lowlands.
In the upper Andaman Sea, strong winds will produce waves 2-4 meters high, with waves exceeding 4 meters in areas with thunderstorms. In the upper Gulf of Thailand, waves will be 2-3 meters high, and over 3 meters in thunderstorm areas. Mariners in the Andaman Sea and Gulf of Thailand should navigate with caution and avoid sailing in areas with thunderstorms. Small boats in the upper Andaman Sea and upper Gulf of Thailand are advised to stay ashore from 6 to 9 August 2026.
For safety and to reduce potential impacts, the public should plan their activities and travel carefully during this period. People are urged to follow announcements from the Meteorological Department and can access information at http://www.tmd.go.th or by calling 0-2399-4012-13 and 1182, available 24 hours.