By Ian Werther in News — 18 Mar 2026

South Korea braces for frost, fog and icy roads, risking supply chain disruption

The Korea Meteorological Administration warned that Thursday will bring a mix of clouds with subfreezing mornings, frost in some inland areas, fog and the risk of icy roads after rain or snow. The agency said chilly conditions will persist, with morning lows around -4 C and daytime highs up to about 16 C.

Dense fog is expected in many inland areas, reducing visibility to less than 200 meters in parts of the southeast and central inland regions, and to under 1 kilometer elsewhere inland. There is also a risk of frost in the early hours across the central and southern inland zones, which could affect agriculture and transport.

We have just come back from a few days in the beautiful Flinders Ranges in South Australia (I managed to sneak the 500 on board and had a few brief opportunities for birding).

I love the Thornbills, they are usually such friendly birds that respond well to my attempts at a type of bird call! This red-eyed species tends to carry it's tail cocked, particularly when people with large white lenses try to imitate their call! — Representative image for context; not directly related to the specific event in this article. License: CC BY-SA 2.0. Source: Wikimedia Commons.

Drivers and pedestrians are advised to exercise caution, as areas that received rain or snow may develop black ice on roads and pavements as temperatures drop overnight and into the morning.

Temperature snapshots across major cities show a broad swing between morning and afternoon. Seoul is forecast to be 1 C in the morning and about 11 C by afternoon. Incheon 1 C / 8 C; Suwon 0 C / 10 C; Chuncheon -3 C / 12 C; Gangneung 4 C / 13 C; Cheongju 2 C / 13 C; Daejeon 1 C / 13 C; Jeonju 1 C / 13 C; Gwangju 2 C / 14 C; Daegu 3 C / 15 C; Busan 6 C / 16 C; Jeju 6 C / 12 C.

Overall, temperatures will align with or be slightly below seasonal norms, with a diurnal range around 15 degrees. Inland areas are likely to see morning lows at or below freezing.

The temperature was below freezing when this fog bank moved along the Petitcodiac river in Moncton. Very cool morning. — Representative image for context; not directly related to the specific event in this article. License: CC BY 2.0. Source: Wikimedia Commons.

Air quality is forecast to be moderate across most of the country, but the capital region, Chungcheong, and Honam are expected to experience higher fine-dust levels into the early morning, while the Gangwon and Yeongnam regions may see poorer air quality as well into the morning hours.

For U.S. readers, the weather matters beyond Korea because icy roads and fog can disrupt travel and logistics in a country that is a major hub for electronics manufacturing and global supply chains. Weather conditions in South Korea can affect commuting patterns, factory shifts, port operations, and the timely delivery of components used by American manufacturers, particularly semiconductors and other high-tech goods. As climate and winter weather patterns influence energy demand and transportation costs, developments in Korea’s winter weather can have indirect effects on markets and suppliers tied to the U.S. economy.

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