East and South brace for heavy rain as monsoon sweeps Thailand

The Thai Meteorological Department’s forecast for Wednesday (June 3, 2026) warned that the southwest monsoon would bring rainstorms to Thailand, with the East and South among the main areas affected.

The South’s west coast is forecast to see thunderstorms over 80% of the area, while Bangkok and surrounding provinces are also set for thunderstorms.

Over the next 24 hours, heavy to very heavy rain is forecast in some areas of the East and South.

Heavy rain is also expected in some parts of the western side of the North and the Central region, including Bangkok and surrounding provinces, as a rather strong southwest monsoon prevails over the Andaman Sea, Thailand and the Gulf of Thailand.

People in these areas are advised to prepare for possible danger from heavy to very heavy rain and accumulated rainfall, which could trigger flash floods and forest run-off, particularly in risk areas near waterways and low-lying areas.

Winds and waves in the Andaman Sea and upper Gulf of Thailand are fairly strong, with waves of 2-3 metres and above 3 metres in thundershowers.

Mariners in the Andaman Sea and Gulf of Thailand are advised to proceed with caution and avoid sailing in areas with thunderstorms, while small boats in the Andaman Sea and upper Gulf should remain ashore during this period.

Weather forecast for Thailand from 6am on Wednesday (June 3) to 6am on Thursday (June 4)

Bangkok and the surrounding provinces

• Thunderstorms are forecast in 60% of the area, with isolated heavy rain.
• Minimum temperature: 26-28°C
• Maximum temperature: 34-36°C
• Southwesterly winds: 10-20 km/h

North

• Thunderstorms are forecast in 40% of the area, with isolated heavy rain in Mae Hong Son, Tak and Kamphaeng Phet.
• Minimum temperature: 22-27°C
• Maximum temperature: 35-38°C
• Southwesterly winds: 10-20 km/h

Northeast

• Thunderstorms are forecast in 40% of the area, mostly in Nong Khai, Bueng Kan, Udon Thani, Sakon Nakhon, Nakhon Phanom, Chaiyaphum, Kalasin, Mukdahan, Nakhon Ratchasima, Buri Ram and Ubon Ratchathani.
• Minimum temperature: 23-26°C
• Maximum temperature: 35-37°C
• Southwesterly winds: 10-20 km/h

Central region

• Thunderstorms are forecast in 40% of the area, with isolated heavy rain in Uthai Thani, Kanchanaburi, Ratchaburi, Suphan Buri and Nakhon Pathom.
• Minimum temperature: 23-26°C
• Maximum temperature: 35-37°C
• Southwesterly winds: 10-20 km/h

East

• Thunderstorms are forecast in 60% of the area, with isolated heavy to very heavy rain in Nakhon Nayok, Prachin Buri, Chon Buri, Rayong, Chanthaburi and Trat.
• Minimum temperature: 24-27°C
• Maximum temperature: 31-36°C
• Southwesterly winds: 20-40 km/h
• Waves: 2-3 metres, rising above 3 metres in thundershowers

South, east coast

• Thunderstorms are forecast in 60% of the area, with isolated heavy rain in Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung and Songkhla.
• Minimum temperature: 23-26°C
• Maximum temperature: 32-35°C
• From Surat Thani northwards: southwesterly winds of 20-40 km/h; waves of 1-2 metres, rising above 2 metres offshore and in thundershowers
• From Nakhon Si Thammarat southwards: southwesterly winds of 20-35 km/h; waves of 1-2 metres, around 2 metres offshore and above 2 metres in thundershowers

South, west coast

• Thunderstorms are forecast in 80% of the area, with isolated heavy to very heavy rain in Ranong, Phang Nga, Phuket, Krabi, Trang and Satun.
• Minimum temperature: 23-25°C
• Maximum temperature: 28-33°C
• Southwesterly winds: 20-40 km/h
• Waves: 2-3 metres, rising above 3 metres in thundershowers