Shorter, warmer cool season expected in Thailand, with lows of 19 deg C in Bangkok

BANGKOK – Thailand’s cool season is expected to begin about a week later than usual in 2026 and bring warmer temperatures than the previous winter, with Bangkok forecast to see lows of around 19 deg C to 21 deg C, according to the Thai Meteorological Department.The department forecasts that upper Thailand will enter the cool season in the third week of October, with conditions lasting until around mid-February 2027.Average minimum temperatures across upper Thailand are expected to be around 22 deg C to 23 deg C, about 2 deg C above the normal average of 19.9 deg C.The forecast suggests the 2026 to 2027 cool season will be milder than in 2025, when the average minimum temperature was 19.6 deg C.The lowest temperatures are expected to fall to around 10 deg C to 12 deg C, mainly in the upper north and north-east.Bangkok is forecast to record minimum temperatures of 19 deg C to 21 deg C, while surrounding provinces could see lows of 18 deg C to 20 deg C.Coldest period expected from late DecemberThe coolest period is expected from late December 2026 to early February 2027.Mountain peaks and highland areas are likely to experience cold to very cold weather, with frost possible on several occasions.From mid-October to mid-November, the north and north-east are expected to experience generally cool conditions, with some cold weather in upper areas.The central and eastern regions could experience cool weather in some northern areas, accompanied by occasional thunder-showers and gusty winds.From mid-November to early February, stronger high-pressure systems from China are expected to bring more persistent cool conditions to upper Thailand.Temperatures are forecast to rise afterwards, with warmer daytime conditions becoming increasingly common.Bangkok to turn cooler from mid-NovemberBangkok and its surrounding provinces are expected to have thunder-showers over about 20% to 30% of the area from mid-October to mid-November.Some days could be cool, with morning fog and occasional gusty winds.From mid-November to early February, cool weather is expected across most of Bangkok and neighbouring provinces, with dense fog possible in some periods.Conditions are then forecast to become more variable as temperatures rise, bringing hot daytime weather to many areas and occasional rain.Heavy rain risk remains in the southWhile upper Thailand moves into the cool season, southern provinces are expected to continue experiencing widespread rain, particularly on the Gulf coast.From mid-October to early January, areas from Chumphon southwards could see thunder-showers over 60% to 80% of the region, with heavy rain in many places and very heavy falls in some areas.The Thai Meteorological Department warned that the conditions could trigger flash floods, forest run-off and overflowing waterways.Waves in the Gulf of Thailand are expected to strengthen periodically, while the Andaman Sea could see waves of around 1m to 2m tall.November and December also carry a higher risk of low-pressure systems developing into tropical cyclones and moving close to or across the Gulf of Thailand and the south.Such systems could bring widespread heavy rain, strong waves and possible storm surges.El Nino could make winter warmerThe meteorological department expects El Nino to strengthen towards the end of 2026 and potentially continue into early 2027.The phenomenon could contribute to temperatures remaining above normal and make Thailand’s cool season less cold than in 2025.The department advised the public to continue monitoring weather forecasts, particularly residents in flood-prone southern areas and people planning trips to mountainous regions during the cool season.