TMD forecasts rain in 30% of upper Thailand on September 30
Southern Thailand faces isolated heavy rain, with thunderstorms forecast across 60% of each coastal region and waves above 2 metres in storms
- The Thai Meteorological Department (TMD) forecasts thunderstorms across 30% of upper Thailand for September 30, affecting Bangkok and the North, Northeast, Central, and Eastern regions.
- This forecast of reduced rain is due to a weakening south-westerly monsoon over the Andaman Sea and the Gulf of Thailand.
- The specific forecast period covers the 24 hours from 6am on September 30 to 6am on October 1.
- In contrast to the upper regions, southern Thailand is expected to have thunderstorms across 60% of its area with isolated heavy downpours.
The Thai Meteorological Department (TMD) forecasts less rain across upper Thailand on Wednesday (September 30), with thunderstorms expected across 30% of each region, including Bangkok and surrounding provinces. Thunderstorms are forecast across 60% of each of the South’s two coastal regions, with isolated heavy downpours. The TMD’s 24-hour forecast covers the period from 6am on September 30 to 6am on October 1, 2026, Thailand time.
The TMD attributed the easing rainfall to a weakening south-westerly monsoon over the Andaman Sea, Thailand and the Gulf of Thailand. Southerly and south-easterly winds are also prevailing over the lower Gulf.
Residents in southern Thailand were urged by the TMD to remain alert to dangers from heavy and accumulated rainfall.
Thunderstorms forecast across 30% of upper Thailand
Bangkok and surrounding provinces: The TMD forecasts thunderstorms across 30% of the metropolitan area during September 30–October 1. Minimum temperatures are expected at 25–27°C and maximum temperatures at 33–35°C, with southerly winds of 10–20km/h.
North: For September 30–October 1, the TMD expects thunderstorms across 30% of the region, mainly in Mae Hong Son, Chiang Mai, Lamphun, Tak, Phitsanulok and Phetchabun. Minimum temperatures will range from 22–25°C and maximum temperatures from 31–35°C, with south-westerly winds of 10–20km/h.
Northeast: Thunderstorms are forecast across 30% of the region during September 30–October 1, mainly in Loei, Chaiyaphum, Nakhon Ratchasima, Buriram, Surin, Sisaket and Ubon Ratchathani, according to the TMD. Minimum temperatures are expected at 23–25°C and maximum temperatures at 33–36°C, with southerly winds of 10–20km/h.
Central region: The TMD’s September 30–October 1 forecast puts thunderstorm coverage at 30%, mainly in Nakhon Sawan, Uthai Thani, Kanchanaburi, Ratchaburi, Samut Sakhon and Samut Songkhram. Minimum temperatures will be 22–25°C and maximum temperatures 33–35°C, with southerly winds of 10–20km/h.
East: The TMD forecasts thunderstorms across 30% of the region during September 30–October 1, mainly in Sa Kaeo, Chonburi, Rayong, Chanthaburi and Trat. Minimum temperatures will range from 24–26°C and maximum temperatures from 32–34°C, while southerly winds will reach 15–30km/h. Waves will be about 1 metre high, exceeding 2 metres in thunderstorms.
Southern coastal regions face isolated heavy rain
South, east coast: The TMD forecasts thunderstorms across 60% of the region during September 30–October 1, with isolated heavy rain in Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla and Yala. Minimum temperatures are expected at 22–25°C and maximum temperatures at 32–35°C, with southerly winds of 15–30km/h. Waves will be about 1 metre high, rising above 2 metres in thunderstorms.
South, west coast: Thunderstorms are expected across 60% of the region during September 30–October 1, with isolated heavy rain in Phang Nga, Krabi, Trang and Satun, according to the TMD. Minimum temperatures will range from 24–26°C and maximum temperatures from 30–34°C.
From Phang Nga northwards, the TMD forecasts south-westerly winds of 15–35km/h during September 30–October 1, with waves of 1–2 metres, exceeding 2 metres in thunderstorms.
From Phuket southwards, the TMD expects south-westerly winds of 15–30km/h during September 30–October 1. Waves will be about 1 metre high and exceed 2 metres in thunderstorms.
Upper Andaman waves could exceed 2 metres in thunderstorms
The TMD’s September 30 marine outlook describes moderate conditions in the upper Andaman Sea, with waves of 1–2 metres and more than 2 metres in thunderstorms. Mariners in both the Andaman Sea and Gulf of Thailand are advised to avoid sailing through thunderstorm areas.
