The Meteorological Department issued its 8th warning about heavy to very heavy rain across Thailand. It listed provinces expected to be affected from 18 to 20 September and advised vigilance for flash floods and mountain runoff floods nearby.
On 18 September 2026, the websiteof the Meteorological Departmentissued announcement No. 8 regarding heavy to very heavy rain across Thailand and strong winds in the Andaman Sea. It stated that from 18 to 20 September 2026, some areas of Thailand will experience heavy rain, with very heavy rain in some parts of the south. This is due to a high pressure system or cold air mass from China spreading over upper northern and upper northeastern regions, causing the monsoon trough to shift over the central, eastern, and upper southern regions. Meanwhile, the fairly strong southwest monsoon winds cover the Andaman Sea, Thailand, and the Gulf of Thailand.
Residents across Thailand are advised to be cautious of heavy to very heavy rain and accumulated rainfall, which may cause flash floods and mountain runoff floods, especially in areas near mountain slopes close to waterways and low-lying areas. People should avoid traveling on routes prone to repeated flooding, particularly lowlands where short-term waterlogging may occur.
The Andaman Sea will experience fairly strong winds with waves 2–3 meters high, and waves over 3 meters in areas with thunderstorms. Fishermen in the Gulf of Thailand and Andaman Sea should navigate cautiously and avoid traveling in areas with thunderstorms. Small boats in the Andaman Sea should refrain from leaving shore from 18 to 20 September 2026.
For safety and to minimize potential impacts, the public is urged to carefully plan their activities and travel during this period. They are encouraged to monitor announcements from the Meteorological Department and can access information anytime via the department’s website at http://www.tmd.go.th or by calling 0-2399-4012-13 and hotline 1182, available 24 hours.
18 September 2026
19 September 2026
20 September 2026
