Summer thunderstorms are expected to hit the North, Northeast, Central Plains and the East of Thailand between Tuesday and Friday, the Meteorological Department said on Saturday.
It said a high-pressure system from China was moving southward and would cover the upper part of Thailand and the South China Sea, causing scattered storms.
During the period, gusty winds and hail are expected to hit the four regions, department chief Wanchai Suk-udomchai said in the warning issued on Saturday.
People should be prepared and stay away from big trees, advertising signboards and unstable structures during the period, the warning said.