Thailand Faces Four-Day Heavy Rain Warning as Monsoon Trough Crosses Southern Region

Key summary

The Thai Meteorological Department (TMD) issued a four-day heavy rain warning for eastern and southern Thailand at 5am on Thursday, October 22, 2026. Persistent rainfall, including heavy to very heavy downpours in some areas, is forecast to continue through October 25. The TMD attributes the wet weather to a monsoon trough crossing central southern Thailand alongside the prevailing southwest monsoon over the lower Andaman Sea. A high-pressure system or cold air mass from China is expected to extend over the upper North, upper Northeast, and South China Sea, bringing easterly winds to Thailand and the Gulf of Thailand. Thunderstorms and isolated strong gusts are forecast for the lower North, lower Northeast, and Central region, including Bangkok and surrounding provinces, during October 22–25. The TMD warns that heavy rain and accumulated rainfall could trigger flash floods and forest run-off near foothills and in low-lying areas. Residents were advised to beware of strong wind gusts and plan daily activities and journeys carefully to reduce potential risks. Waves in the Andaman Sea and Gulf of Thailand are forecast to exceed three metres in areas experiencing thunderstorms, prompting a caution for mariners to navigate carefully and avoid sailing through thunderstorms. The TMD scheduled its next warning for 5pm on October 22. Weather information is available around the clock via the TMD website or by calling 02-399-4012, 02-399-4013, or 1182.