Thailand weather forecast: Monsoon brings more rain, Northeast sees 70% coverage

Thailand will experience increased rainfall on Wednesday (August 5, 2026), with the Northeast expected to see thunderstorms across 70% of the region and some areas facing heavy to very heavy rain, according to the Thai Meteorological Department.

The department said the conditions are being driven by a monsoon trough extending across the upper North and upper Laos before moving into a low-pressure area near the upper coast of Vietnam. A strengthening southwest monsoon is also affecting the Andaman Sea, Thailand and the Gulf of Thailand.

People in affected areas have been warned to remain alert for heavy to very heavy rainfall and accumulated rain, which could lead to flash floods and forest run-off, particularly in foothill areas near waterways and low-lying locations.

Strong winds and rough seas expected

The Meteorological Department warned that winds over the Andaman Sea and Gulf of Thailand will strengthen.

The upper Andaman Sea will see waves of 2-3 metres, with waves exceeding 3 metres in areas experiencing thunderstorms.
The lower Andaman Sea and upper Gulf of Thailand will have waves of around 2 metres, with waves above 2 metres during thunderstorms.
Mariners are advised to exercise caution and avoid areas affected by thunderstorms.
Small boats in the upper Andaman Sea should remain ashore.

The department also reported that a tropical depression in the South China Sea has strengthened into Tropical Storm Kujira and is moving towards the northern Philippines. The storm will not enter Thailand, but travellers heading to the area are advised to check weather conditions before departure.

Weather forecast from 6am Wednesday to 6am Thursday

Bangkok and surrounding provinces

• Thunderstorms in 60% of the area, with isolated heavy rain.
• Minimum temperature: 24-28°C.
• Maximum temperature: 33-35°C.
• Southwest winds: 10-25 km/h.

North

• Thunderstorms in 60% of the area, with isolated heavy rain.
• Heavy rain possible in Mae Hong Son, Chiang Mai, Chiang Rai, Lampang, Phayao, Phrae, Nan, Uttaradit, Phitsanulok and Phetchabun.
• Minimum temperature: 23-27°C.
• Maximum temperature: 32-35°C.
• Southwest winds: 10-20 km/h.

Northeast

• Thunderstorms in 70% of the area, with isolated heavy rain.
• Heavy rain possible in Nong Khai, Udon Thani, Sakon Nakhon, Kalasin, Mukdahan, Yasothon, Amnat Charoen and Ubon Ratchathani.
• Very heavy rain possible in some areas of Bueng Kan and Nakhon Phanom.
• Minimum temperature: 23-26°C.
• Maximum temperature: 29-34°C.
• Southwest winds: 10-20 km/h.

Central region

• Thunderstorms in 60% of the area, with isolated heavy rain.
• Heavy rain possible in Nakhon Sawan, Lop Buri, Saraburi, Phra Nakhon Si Ayutthaya, Kanchanaburi, Ratchaburi and Nakhon Pathom.
• Minimum temperature: 25-27°C.
• Maximum temperature: 34-36°C.
• Southwest winds: 10-25 km/h.

East

• Thunderstorms in 60% of the area, with isolated heavy rain.
• Heavy rain possible in Nakhon Nayok, Prachin Buri, Chanthaburi and Trat.
• Minimum temperature: 23-28°C.
• Maximum temperature: 31-35°C.
• Southwest winds: 20-35 km/h.
• Seas: waves around 2 metres, rising above 2 metres during thunderstorms.

South (east coast)

• Thunderstorms in 60% of the area, with isolated heavy rain.
• Heavy rain possible in Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala and Narathiwat.
• Minimum temperature: 23-26°C.
• Maximum temperature: 33-36°C.
• Southwest winds: 15-35 km/h.
• Seas: waves around 1 metre offshore, rising to 1-2 metres offshore and above 2 metres during thunderstorms.

South (west coast)

• Thunderstorms in 70% of the area, with isolated heavy rain.
• Heavy rain possible in Ranong, Phang Nga, Phuket and Krabi.
• Minimum temperature: 23-27°C.
• Maximum temperature: 32-34°C.

From Phuket northwards:

• Southwest winds: 20-40 km/h.
• Seas: waves 2-3 metres, exceeding 3 metres during thunderstorms.

From Krabi southwards:

• Southwest winds: 20-35 km/h.
• Seas: waves around 2 metres, exceeding 2 metres during thunderstorms.