Thailand under strong monsoon with widespread rain and high waves
Heavy to very heavy rain is expected in several regions, with thundershowers across 60% of Bangkok and waves above three metres in the upper Andaman Sea.
- A strong south-west monsoon is causing widespread heavy rain across Thailand, with the North, Northeast, East, and South regions being particularly affected.
- The weather conditions are generating high waves, expected to reach 2-3 meters in the upper Andaman Sea and around 2 meters in the lower Andaman Sea and upper Gulf of Thailand.
- Authorities have issued warnings for potential flash floods and have advised mariners to navigate with caution, urging small boats in the upper Andaman Sea to remain ashore.
The Thai Meteorological Department (TMD) warned that monsoon conditions would bring heavy rain to several parts of Thailand on Wednesday (July 15, 2026), with thundershowers expected across 60% of Bangkok and its vicinity.
Over the next 24 hours, isolated heavy rain is expected in the North, Northeast and South, with isolated very heavy rain in the East.
A low-pressure cell is covering upper Vietnam, while the rather strong south-west monsoon is prevailing over the Andaman Sea, Thailand and the Gulf of Thailand.
Residents in affected areas are advised to beware of heavy to very heavy rain and accumulated rainfall, which could cause flash floods and forest run-off, particularly on foothill slopes near waterways and in low-lying areas.
Waves in the upper Andaman Sea are expected to reach 2-3 metres and exceed 3 metres during thundershowers.
In the lower Andaman Sea and upper Gulf of Thailand, waves will be around 2 metres and exceed 2 metres during thundershowers.
Mariners are advised to navigate with caution and avoid areas affected by thundershowers.
Small boats in the upper Andaman Sea should remain ashore for one more day.
Weather across Thailand from 6am on Wednesday (July 15) to 6am on Thursday (July 16)
Bangkok and its vicinity
- Thundershowers across 60% of the area.
- Minimum temperature: 24-27°C
- Maximum temperature: 33-35°C
- South-westerly winds: 10-25 km/h
North
- Thundershowers across 40% of the area, with isolated heavy rain in Mae Hong Son, Chiang Mai, Tak, Phitsanulok and Phetchabun.
- Minimum temperature: 23-26°C
- Maximum temperature: 32-35°C
- South-westerly winds: 10-20 km/h
Northeast
- Thundershowers across 40% of the area, with isolated heavy rain in Nong Khai, Bueng Kan, Sakon Nakhon, Nakhon Phanom, Udon Thani, Mukdahan, Amnat Charoen and Ubon Ratchathani.
- Minimum temperature: 22-25°C
- Maximum temperature: 33-36°C
- South-westerly winds: 10-20 km/h
Central region
- Thundershowers across 40% of the area, mainly in Nakhon Sawan, Uthai Thani, Chai Nat, Suphan Buri, Phra Nakhon Si Ayutthaya, Saraburi, Kanchanaburi, Ratchaburi, Nakhon Pathom, Samut Songkhram and Samut Sakhon.
- Minimum temperature: 24-25°C
- Maximum temperature: 34-36°C
- South-westerly winds: 10-25 km/h
East
- Thundershowers across 60% of the area, with heavy rain in Nakhon Nayok and Prachin Buri and isolated very heavy rain in Chanthaburi and Trat.
- Minimum temperature: 24-28°C
- Maximum temperature: 31-35°C
- South-westerly winds: 20-35 km/h
- Waves will be around 2 metres and exceed 2 metres during thundershowers.
South (east coast)
- Thundershowers across 40% of the area, mainly in Phetchaburi, Prachuap Khiri Khan, Chumphon, Surat Thani and Nakhon Si Thammarat.
- Minimum temperature: 24-25°C
- Maximum temperature: 32-35°C
- From Surat Thani northwards, south-westerly winds will reach 20-35 km/h. Waves will be 1-2 metres, around 2 metres offshore and above 2 metres during thundershowers.
- From Nakhon Si Thammarat southwards, south-westerly winds will reach 15-35 km/h. Waves will be around 1 metre, rising to 1-2 metres offshore and above 2 metres during thundershowers.
South (west coast)
- Thundershowers across 60% of the area, with isolated heavy rain in Ranong, Phang Nga and Phuket.
- Minimum temperature: 23-25°C
- Maximum temperature: 30-34°C
- From Phuket northwards, south-westerly winds will reach 20-40 km/h. Waves will be 2-3 metres and exceed 3 metres during thundershowers.
- From Krabi southwards, south-westerly winds will reach 20-35 km/h. Waves will be around 2 metres and exceed 2 metres during thundershowers.
