TMD warns heavy rain across Thailand from storm Maysak and monsoon

The Thai Meteorological Department (TMD) warned on Sunday (July 5, 2026) that all regions would face heavy rain, with the highest rainfall coverage reaching 70% of the area, especially in the North, Northeast, and Bangkok and its surrounding provinces. People were urged to watch for possible flash floods.

For the next 24 hours, isolated very heavy rain is forecast in the upper North, upper Northeast and East as the monsoon trough lies across the upper North and upper Laos and feeds into severe tropical storm “Maysak”.

The rather strong southwest monsoon is also covering the Andaman Sea, Thailand and the Gulf of Thailand.

People are advised to be wary of heavy to very heavy rain and accumulated rainfall, which could trigger flash floods and forest runoff, especially in the foothills near waterways and in low-lying areas.

Waves in the upper Andaman Sea are expected to be rather strong, reaching 2-3 metres and rising above 3 metres in thunderstorm areas.

In the lower Andaman Sea and upper Gulf of Thailand, waves are forecast at about 2 metres, with waves above 2 metres during thunderstorms.

All vessels in the Andaman Sea and the Gulf of Thailand are advised to navigate with caution and avoid thunderstorm areas, while small boats in the upper Andaman Sea should remain ashore.

Weather forecast for Thailand from 6am on Sunday (July 5) to 6am on Monday (July 6)

Bangkok and surrounding provinces

• Rain or thundershowers are forecast for 60% of the area.
• Minimum temperature: 25-27 degrees Celsius
• Maximum temperature: 30-34 degrees Celsius
• Southwesterly winds: 10-25 kilometres per hour

North

• Thundershowers are forecast for 70% of the area, with heavy rain in Mae Hong Son, Chiang Mai, Lampang, Phayao, Phrae, Uttaradit, Phitsanulok and Phetchabun, and isolated very heavy rain in Tak, Chiang Rai and Nan.
• Minimum temperature: 23-25 degrees Celsius
• Maximum temperature: 31-34 degrees Celsius
• Southwesterly winds: 10-20 kilometres per hour

Northeast

• Thundershowers are forecast for 70% of the area, with heavy rain in Loei, Udon Thani, Sakon Nakhon and Mukdahan, and isolated very heavy rain in Nong Khai, Bueng Kan and Nakhon Phanom.
• Minimum temperature: 23-26 degrees Celsius
• Maximum temperature: 30-34 degrees Celsius
• Southwesterly winds: 10-20 kilometres per hour

Central region

• Thundershowers are forecast for 60% of the area, with heavy rain in Ratchaburi and Uthai Thani, and isolated very heavy rain in Kanchanaburi.
• Minimum temperature: 24-26 degrees Celsius
• Maximum temperature: 32-35 degrees Celsius
• Southwesterly winds: 10-25 kilometres per hour

East

• Thundershowers are forecast for 70% of the area, with heavy rain in Nakhon Nayok, Prachin Buri, Sa Kaeo, Chachoengsao, Chon Buri and Rayong, and isolated very heavy rain in Chanthaburi and Trat.
• Minimum temperature: 24-27 degrees Celsius
• Maximum temperature: 30-32 degrees Celsius
• Southwesterly winds: 20-35 kilometres per hour
• Waves are expected to be about 2 metres high, rising above 2 metres during thunderstorms.

South (east coast)

• Thundershowers are forecast for 30% of the area, mostly in Phetchaburi, Prachuap Khiri Khan and Narathiwat.
• Minimum temperature: 23-24 degrees Celsius
• Maximum temperature: 32-35 degrees Celsius
• From Surat Thani northwards: Southwesterly winds of 20-35 kilometres per hour. Waves are forecast at 1-2 metres, rising above 2 metres offshore and during thunderstorms.
• From Nakhon Si Thammarat southwards: Southwesterly winds of 15-30 kilometres per hour. Waves are forecast at about 1 metre, rising above 2 metres during thunderstorms.

South (west coast)

• Thundershowers are forecast for 30% of the area, mostly in Ranong and Phang Nga.
• Minimum temperature: 23-25 degrees Celsius
• Maximum temperature: 32-36 degrees Celsius
• From Phuket northwards: Southwesterly winds of 20-40 kilometres per hour. Waves are forecast at 2-3 metres, rising above 3 metres during thunderstorms.
• From Krabi southwards: Southwesterly winds of 20-35 kilometres per hour. Waves are forecast at about 2 metres, rising above 2 metres during thunderstorms.