Heavy rain and gusty winds raise flash flood risk in upper Thailand

The Thai Meteorological Department (TMD) has warned of thundershowers, gusty winds and isolated heavy to very heavy rain in upper Thailand from October 4 to 7, 2026.

The affected areas are:

• October 4: The upper and eastern parts of the North, and the Northeast.
• October 5–6: The North, Central region, including Bangkok and surrounding areas, the East and upper South. Rainfall in the Northeast is expected to decrease.
• October 7: Western parts of the North and Central region.

The unsettled weather is caused by a high-pressure system, or cold air mass, from China extending over the North and upper Northeast late in the rainy season, initially triggering thundershowers.

The southwest monsoon continues to prevail over the Andaman Sea, the South and the Gulf of Thailand.

Heavy and accumulated rainfall could cause flash floods and sudden runoff from higher ground, particularly on foothill slopes near waterways and in low-lying areas.

Standing floodwater is also possible in low-lying areas.

People should beware of gusty winds and avoid open spaces or areas beneath large trees or unsecured billboards.

Winds and waves in the Andaman Sea and Gulf of Thailand are expected to strengthen, with waves exceeding two metres in thundershowers.

Mariners should check their routes, navigate cautiously and avoid sailing through thundershowers.

Rain is expected to continue in the East and South during October 8–13, with isolated heavy to very heavy rainfall.

People are advised to follow weather forecasts closely.

North

• Thundershowers are forecast over 30% of the region, with isolated heavy rain and gusty winds in Chiang Rai, Phayao, Nan, Phrae, Uttaradit, Sukhothai and Phitsanulok.
• Minimum temperature: 23–27°C.
• Maximum temperature: 33–38°C.
• Southwesterly winds: 10–15 km/h.

Northeast

• Thundershowers are forecast over 40% of the region, with isolated heavy rain and gusty winds in Loei, Nong Bua Lam Phu, Udon Thani, Nong Khai, Bueng Kan, Sakon Nakhon, Nakhon Phanom, Mukdahan, Yasothon, Kalasin, Roi Et, Amnat Charoen, Sisaket and Ubon Ratchathani.
• Minimum temperature: 23–25°C.
• Maximum temperature: 32–35°C.
• Southeasterly winds: 10–15 km/h.

Central region

• Thundershowers are forecast over 40% of the region, with isolated gusty winds, mainly in Lop Buri, Saraburi, Phra Nakhon Si Ayutthaya, Suphan Buri, Kanchanaburi, Ratchaburi and Nakhon Pathom.
• Minimum temperature: 23–27°C.
• Maximum temperature: 35–37°C.
• Southerly winds: 10–15 km/h.

East

• Thundershowers are forecast over 40% of the region, with isolated gusty winds, mainly in Nakhon Nayok, Prachin Buri, Chachoengsao, Chon Buri, Rayong, Chanthaburi and Trat.
• Minimum temperature: 24–27°C.
• Maximum temperature: 32–35°C.
• Southeasterly winds: 10–30 km/h.
• Waves below one metre, exceeding two metres in thundershowers.

South — east coast

• Thundershowers are forecast over 40% of the region, with isolated heavy rain in Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Yala and Narathiwat.
• Minimum temperature: 23–25°C.
• Maximum temperature: 33–35°C.
• Westerly winds: 10–30 km/h.
• Waves below one metre, exceeding two metres in thundershowers.

South — west coast

• Thundershowers are forecast over 60% of the region, with isolated heavy rain in Phang Nga, Phuket, Krabi, Trang and Satun.
• Minimum temperature: 23–26°C.
• Maximum temperature: 31–34°C.
• Northwesterly winds: 15–30 km/h.
• Waves around one metre, exceeding two metres in thundershowers.

Bangkok and surrounding areas

• Thundershowers are forecast over 40% of the area, with isolated gusty winds.
• Minimum temperature: 26–27°C.
• Maximum temperature: 33–36°C.
• Southerly winds: 10–15 km/h.