TMD warns 60 Thai provinces of heavy rain as monsoon intensifies

The Thai Meteorological Department (TMD) forecast on Tuesday (June 30, 2026) that Thailand would see isolated heavy rain over the next 24 hours, with very heavy rain in some areas along the west coast of the East and the South.

The conditions are being driven by the strengthening southwest monsoon over the Andaman Sea, Thailand, and the Gulf of Thailand, together with the monsoon trough extending from the upper North and upper Laos into a low-pressure cell over upper Vietnam.

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

Sea conditions in the upper Andaman Sea are expected to be fairly strong, with waves 2-3 metres high and above 3 metres in thundershowers.

In the lower Andaman Sea and the upper Gulf of Thailand, waves are expected to be about 2 metres high and above 2 metres in thundershowers.

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

Weather forecast for Thailand from 6am on Tuesday (June 30) to 6am on Wednesday (July 1)

North

• Thundershowers are forecast in 70% of the area, with isolated heavy rain in Mae Hong Son, Chiang Mai, Chiang Rai, Lamphun, Lampang, Phayao, Nan, Phrae, Uttaradit, Tak and Phitsanulok.
• Minimum temperature: 23-27°C
• Maximum temperature: 32-36°C
• Southwesterly winds: 10-20 km/h

Northeast

• Thundershowers are forecast in 70% of the area, with isolated heavy rain in Loei, Nong Khai, Bueng Kan, Nong Bua Lam Phu, Udon Thani, Sakon Nakhon, Nakhon Phanom, Kalasin, Mukdahan, Roi Et, Yasothon, Amnat Charoen and Ubon Ratchathani.
• Minimum temperature: 23-26°C
• Maximum temperature: 31-36°C
• Southwesterly winds: 10-20 km/h

Central region

• Thundershowers are forecast in 60% of the area, with isolated heavy rain in Saraburi, Phra Nakhon Si Ayutthaya, Kanchanaburi, Nakhon Pathom and Samut Sakhon.
• Minimum temperature: 24-26°C
• Maximum temperature: 34-36°C
• Southwesterly winds: 10-20 km/h

East

• Thundershowers are forecast in 70% of the area, with isolated heavy to very heavy rain in Nakhon Nayok, Prachin Buri, Chachoengsao, Chon Buri, Rayong, Chanthaburi and Trat.
• Minimum temperature: 24-28°C
• Maximum temperature: 30-35°C
• Southwesterly winds: 20-35 km/h
• The sea is expected to have waves about 2 metres high and above 2 metres in thundershowers.

South (east coast)

• Thundershowers are forecast in 60% of the area, with isolated heavy rain in Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, Yala and Narathiwat.
• Minimum temperature: 23-26°C
• Maximum temperature: 33-35°C
• From Surat Thani northwards: southwesterly winds of 20-35 km/h. Waves are expected to be 1-2 metres high, and above 2 metres offshore and in thundershowers.
• From Nakhon Si Thammarat southwards: southwesterly winds of 15-30 km/h. Waves are expected to be about 1 metre high and above 2 metres in thundershowers.

South (west coast)

• Thundershowers 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: 23-26°C
• Maximum temperature: 29-33°C
• From Phang Nga northwards: southwesterly winds of 20-40 km/h. Waves are expected to be 2-3 metres high and above 3 metres in thundershowers.
• From Phuket southwards: southwesterly winds of 20-35 km/h. Waves are expected to be about 2 metres high and above 2 metres in thundershowers.

Bangkok and vicinity

• Thundershowers are forecast in 60% of the area, with isolated heavy rain.
• Minimum temperature: 25-27°C
• Maximum temperature: 33-35°C
• Southwesterly winds: 10-20 km/h