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Mercury dips to 12 degrees in some areas as autumn weather arrives in earnest

Published: 21 Sep. 2025, 15:22 Updated: 21 Sep. 2025, 17:38

People sit on picnic mats and watch performances at a jazz festival at Seoul Forest in eastern Seoul on Sept. 21. [YONHAP]

Cooler mornings signaled the arrival of autumn on Sunday, with temperatures dipping to as low as 12 degrees Celsius (53 degrees Fahrenheit) in some inland areas.

The Korea Meteorological Administration (KMA) advised people to take precautions as day-to-night temperature swings reached about 10 degrees Celsius in several regions.

Korea saw morning lows ranging from 13 to 20 degrees Celsius and afternoon highs between 23 and 28 degrees Celsius on Sunday, close to seasonal averages. Similar conditions are expected through Tuesday, according to a KMA forecast.

Morning lows on Monday will range from 12 to 21 degrees Celsius, with highs of 23 to 29 degrees Celsius. Most major cities, including Seoul, Incheon, Daejeon, and Daegu, will experience temperatures in the mid-20s, with slightly warmer conditions in the southwest, where cities such as Gwangju and Jeonju, North Jeolla, are expected to reach 27 degrees Celsius.

On Tuesday, the morning temperatures are expected to range from 14 to 22 degrees Celsius, with daytime highs of 23 to 28 degrees.

People walk on trail at Mount Namsan in central Seoul on Sept. 18. [YONHAP]

“Inland areas will see significant temperature differences of about 10 degrees [Celsius] between day and night, so people should take care of their health,” the KMA said.

Some parts of the country experienced cloudy skies and even light rain from Sunday through Monday. The eastern coast of Gangwon is expected to receive around 5 millimeters (0.1 inches) of rain, while less than 0.1 millimeter of drizzle may fall along the North Gyeongsang coast and in Ulsan. Jeju Island is forecast to receive 5 to 20 millimeters of rain through Monday.

Winds are expected to gust up to around 15 meters per second along the east coast and the southern coast of South Gyeongsang on Sunday, and along the South Jeolla and South Gyeongsang coasts on Monday and Tuesday, while gusts may reach 20 meters per second in the mountainous areas of Jeju Island. The KMA urged the public to take precautions against damage to facilities and safety accidents.

Starting Sunday afternoon, winds strengthen and waves rise in the far southern waters off South Gyeongsang. From Monday, rough seas are expected to spread to the southern Yellow Sea, the western South Sea, and waters around Jeju Island, where the KMA may issue a high seas warning.

Skies will be partly cloudy across the country on Monday, with occasional rain falling over parts of Jeju Island through the morning. Fine dust levels will stay at “good” nationwide as air circulation disperses pollutants.

This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.
BY NAM SOO-HYUN [[email protected]]