Strong waves forecast off Phuket as monsoon warning runs May 28 to June 1

Thailand’s Meteorological Department has warned of strong waves in the upper Andaman Sea from Phuket northward during May 28 to June 1, with seas forecast at 2 to 3 metres and above 3 metres in thundershowers.

The warning was issued in the department’s announcement No. 2 (80/2569), signed by Meteorological Department director-general Sukanyanee Yawinchan. The department said a fairly strong southwest monsoon covering the Andaman Sea, Thailand and the Gulf of Thailand, together with a monsoon trough across upper Thailand, would bring increased rain and rougher seas.

For waters in the upper Andaman Sea, from Phuket northward, waves are expected to reach 2 to 3 metres. In areas with thunderstorms, waves are forecast to rise above 3 metres.

The department advised mariners in the Andaman Sea and Gulf of Thailand to proceed with caution and avoid sailing in thunderstorm areas. Small boats in the upper Andaman Sea were advised to stay ashore during the period.

The same weather system is also expected to bring more rain across Thailand, with heavy to very heavy falls in some places, raising the risk of flash flooding and runoff, especially in low-lying areas and near waterways.

The department said its next announcement would be issued at 5am on May 28, 2026.