More rain forecast across Thailand as southwest monsoon strengthens

The Thai Meteorological Department (TMD) has issued its weather forecast for Sunday (June 28, 2026).

From Sunday (June 28, 2026) to Friday (July 3, 2026), Thailand will see more rain, with isolated heavy to very heavy rain, particularly in the eastern region and the southern region’s west coast.

This is because a monsoon trough will lie across the northern region and the upper northeastern region, while the southwest monsoon prevailing over the Andaman Sea, Thailand and the Gulf of Thailand will strengthen.

People in those areas are advised to beware of heavy to very heavy rain and accumulated rainfall, which may cause flash floods and forest run-off, especially on foothill slopes near waterways and in low-lying areas.

From Monday (June 29, 2026) to Friday (July 3, 2026)

Wave conditions in the upper Andaman Sea will be rather strong, with waves 2-3 metres high and more than 3 metres during thunderstorms.

The lower Andaman Sea and the upper Gulf of Thailand will have waves about 2 metres high, rising to more than 2 metres during thunderstorms.

Seafarers in the Andaman Sea and Gulf of Thailand are advised to navigate with caution and avoid sailing in areas with thunderstorms.

Small boats in the upper Andaman Sea should remain ashore during this period.

To ensure safety and reduce possible impacts, people are advised to plan their daily activities and travel carefully during the period.

They are also advised to follow announcements from the Thai Meteorological Department and information on the department’s website.

Weather forecast for Thailand, Sunday (June 28, 2026)

Northern region

• Thunderstorms are forecast in 40% of the area, with isolated heavy rain in Tak and Kamphaeng Phet.
• Minimum temperature: 23-28°C.
• Maximum temperature: 34-36°C.
• Southwesterly winds: 10-20 km/h.

Northeastern region

• Thunderstorms are forecast in 40% of the area, with isolated heavy rain in Nong Khai, Bueng Kan, Sakon Nakhon and Nakhon Phanom.
• Minimum temperature: 24-26°C.
• Maximum temperature: 35-37°C.
• Southwesterly winds: 10-20 km/h.

Central region

• Thunderstorms are forecast in 60% of the area, with isolated heavy rain in Nakhon Sawan, Uthai Thani, Kanchanaburi and Ratchaburi.
• Minimum temperature: 25-27°C.
• Maximum temperature: 35-36°C.
• Southwesterly winds: 10-20 km/h.

Eastern region

• Thunderstorms are forecast in 60% of the area, with isolated heavy to very heavy rain in Chanthaburi and Trat.
• Minimum temperature: 24-28°C.
• Maximum temperature: 31-37°C.
• Southwesterly winds: 20-35 km/h.
• Waves will be about 2 metres high, rising to more than 2 metres during thunderstorms.

Southern region, east coast

• Thunderstorms are forecast in 40% of the area, with isolated heavy rain in Chumphon and Surat Thani.
• Minimum temperature: 23-26°C.
• Maximum temperature: 35-36°C.
• From Surat Thani northwards: southwesterly winds of 15-35 km/h; waves about 1 metre high, rising to 1-2 metres offshore.
• During thunderstorms, waves will exceed 2 metres.
• From Nakhon Si Thammarat southwards: southwesterly winds of 15-30 km/h; waves about 1 metre high, rising to more than 2 metres during thunderstorms.

Southern region, west coast

• Thunderstorms are forecast in 70% 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: 31-35°C.
• From Phang Nga northwards: southwesterly winds of 20-35 km/h; waves about 2 metres high, rising to more than 2 metres during thunderstorms.
• From Phuket southwards: southwesterly winds of 15-35 km/h; waves 1-2 metres high, rising to more than 2 metres during thunderstorms.

Bangkok and the surrounding areas

• Thunderstorms are forecast in 60% of the area, with isolated heavy rain.
• Minimum temperature: 26-27°C.
• Maximum temperature: 34-36°C.
• Southwesterly winds: 10-20 km/h.