Tomorrow morning, temperatures will drop 1-5 degrees Celsius lower than today... most areas below 5 degrees Celsius.

Inland central and northern Gyeongbuk inland areas will be below freezing... daytime highs will remain between 10-18 degrees Celsius.

Caused by cold air at -20 degrees Celsius carried by the northerly wind... expected to ease by Wednesday afternoon.

Commuting in early winter chill (Seoul=Yonhap News) Reporter Kim In-cheol = Citizens commute on Sejong-daero intersection in Jongno-gu, Seoul, on October 27, as the morning temperature drops to 4 degrees Celsius, signaling early winter weather. 2025.10.27 yatoya@yna.co.kr

The chill that made people hunch on Monday, the 27th, will only start to subside by Wednesday afternoon, the 29th.

This morning was the coldest of the autumn so far.

In central regions, morning temperatures hovered around 5 degrees Celsius.

High mountain areas in Gangwon, such as Seoraksan and Gwangdeoksan, saw morning temperatures drop below minus 5 degrees Celsius.

In several northern areas of Gyeonggi and Gangwon, including Paju, Gyeonggi (Panwa, lowest morning temperature minus 1.5 degrees Celsius), Yeoncheon, Gyeonggi (Baekhak, minus 1.4 degrees Celsius), and Cheorwon, Gangwon (Gimhwa, minus 1.0 degrees Celsius), the lowest temperatures fell below freezing.

The reason for this cold snap, with morning temperatures dropping about 5-10 degrees Celsius compared to the previous day, is that a trough in the upper atmosphere north of Korea has drawn in cold air from the north. Currently, the air at an altitude of 5 kilometers above Korea is around minus 20 degrees Celsius.

The cold air in the upper atmosphere is also supporting the development of a high-pressure system at lower altitudes.

As a result, a high-pressure system located in northeastern China is expanding towards the west coast, and cold northerly winds are blowing at ground level along its edges, intensifying the cold.

On Tuesday, the 28th, morning temperatures are expected to drop another 1-5 degrees Celsius compared to today.

Inland central and northern Gyeongbuk inland areas will have morning temperatures below 0 degrees Celsius, while other regions will remain below 5 degrees Celsius.

Although the inflow of cold air from the north will not intensify further, the night of the 27th to the 28th will see active radiative cooling, making the 28th colder.

Radiative cooling is a phenomenon where the energy radiated from the Earth's surface exceeds the energy absorbed, causing temperatures to drop rapidly. It occurs well during 'clear and dry autumn days' like these.

The lowest morning temperatures nationwide on the 28th will range between minus 3 and 8 degrees Celsius, with daytime high temperatures remaining between 10-18 degrees Celsius.

On the 28th, morning temperatures in Yangju, Gyeonggi, and Cheorwon, Hwacheon, and Pyeongchang, Gangwon will drop to minus 3 degrees Celsius.

The lowest morning temperatures in Seoul and Daejeon are expected to be 2 degrees Celsius, in Incheon and Daegu 3 degrees Celsius, in Ulsan 4 degrees Celsius, and in Gwangju and Busan 7 degrees Celsius.

On Wednesday, the 29th, morning temperatures will remain cool, between 1-9 degrees Celsius.

After that, by the afternoon of the 29th, temperatures will rise to 15-20 degrees Celsius, returning to average levels.

This warming will occur as the trough that was pushing cold air into Korea moves eastward, changing the wind direction over Korea to westerly.

From the 27th to the 29th, frost or ice may form in many inland areas, potentially causing cold damage, so preparations should be made.

Additionally, there will be a significant temperature difference of around 10 degrees Celsius between day and night, so attention should be paid to clothing choices. Yonhap News