Monthly Weather Summary

In November 2025, the weak high-pressure area covered upper northern and northeastern regions of Thailand during the beginning of the month. After that, the ridge of high-pressure area from China periodically extended to dominate upper Thailand in the middle and the end of the month, occasionally expanding to cover the upper southern region. In addition, the northeast monsoon prevailed over the Gulf of Thailand, the southern region and the Andaman Sea almost the entire month. At the end of the month, an active high-pressure area extended to cover upper Thailand and the upper southern region causing a decrease in temperature with generally cool and cold weather across the country. Cold weather was observed in most areas of the northern and northeastern regions with very cold weather reported in some places. For rainfall, upper Thailand received unusual rain in the beginning and the middle of November due to the influence of monsoon trough lying over the central, eastern, and lower northeastern region during the beginning of the month together with the confluence of the easterly and southeasterly winds over the northern and central regions and the prevailing of the easterly and southeasterly winds over lower northeastern, eastern, and lower central at times. Moreover, typhoon “KALMAEGI (2525)” made landfall at Binh Dinh, Vietnam before moving inland across Cambodia and Laos and weakening into a tropical depression. The storm entered northeastern region of Thailand at Sirindhorn district, Ubon Ratchathani province on 7 November and subsequently weakened into an active low-pressure area covering the northeastern and northern regions and covering Myanmar. In southern Thailand, the monsoon trough lay across the upper southern region at the beginning of the month. The northeast monsoon prevailed over the Gulf of Thailand, the southern region and the Andaman Sea almost the whole month and became rather strong at the end of the month. Furthermore, the low-pressure cell covered the lower Gulf of Thailand and lower southern region during 19-21 November, before moving to cover the lower Andaman Sea and Malaysia during 22-25 November and later covered the lower Andaman Sea and the Strait of Malacca. These factors led to continuous rainfall across the central and lower southern regions of Thailand, with heavy to very heavy rainfall occurring in many areas of Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala, Narathiwat, Trang, and Satun provinces. In particular, during 21-25 November, successive torrential rain was reported in Songkhla province (Hat Yai, Kho Hong, and Sadao districts) as well as in Pattani, Yala, and Narathiwat provinces. This resulted in flooding in several areas, with severe flooding in Hat Yai district, Songkhla province. Overall, the average total rainfall across Thailand in November 2025 was 129% above normal, with the new highest 1-day rainfall and monthly total rainfall exceeded the previous record in some stations. Monthly rainfall was above normal rainfall in all regions i.e. northern region 96.6 mm (359%), northeastern region 37.3 mm (203%), central received 112.1 mm (353%), eastern region 43.2 mm (90%), southern region (east coast) 311.3 mm (91%) and southern region (west coast) 188.0 mm (97%). The average temperature across Thailand was 0.7 °C below normal. Further details are provided below.