The Meteorological Department issued its 9th announcement listing provinces at risk. "Heavy to very heavy rain". Monitoring for flash floods and rapid runoff from hills; warning of relatively strong winds and waves in the upper Andaman Sea.
On 31 May 2026, the websiteof the Meteorological Departmentreleased Announcement No. 9 regarding heavy to very heavy rain over Thailand and strong winds in the Andaman Sea, effective until 1 June 2026.
It stated that Thailand is experiencing continuous rain with some heavy showers. Very heavy rain is expected in some areas of the western southern region. This is due to the southwest monsoon covering the Andaman Sea, the south, and the Gulf of Thailand with considerable strength, combined with a monsoon trough passing over upper Thailand. The public in Thailand is advised to prepare for hazards from heavy to very heavy rain and accumulated rainfall that may cause flash floods and rapid runoff, especially in areas near waterways and lowlands.
For the upper Andaman Sea, from Phuket province northward, winds are relatively strong with waves 2-3 meters high. In areas with thunderstorms, waves exceed 3 meters. The lower Andaman Sea, from Krabi province southward, and the upper Gulf of Thailand have waves about 2 meters high, rising above 2 meters in thunderstorms. Mariners in these areas should navigate cautiously and avoid sailing in thunderstorms. Small boats in the upper Andaman Sea are advised to stay ashore during this period.
The public is urged to follow announcements from the Meteorological Department and can access information on their website.http://www.tmd.go.thor by calling 0-2399-4012-13 and 1182, available 24 hours.
Provinces expected to be affected by very heavy rain are as follows:
Provinces expected to be affected by very heavy rain
Provinces expected to be affected by heavy rain
Provinces expected to be affected by very heavy rain
Provinces expected to be affected by heavy rain