By Ian Werther in News — 14 Mar 2026

South Korea Faces Frost Inland, Sharp Temperature Swings, Coastal Swells

The Korea Meteorological Administration says Saturday, March 14, 2026, will be a day of partly cloudy skies nationwide as a high-pressure system moves eastward along the northern edge of the East Sea. The setup should keep conditions relatively calm but with notable temperature swings between day and night.

Morning temperatures across the country are expected to range from -4 to 4 degrees Celsius, with daytime highs from 10 to 15 degrees. Those values are close to the March normals, which average lows of -4 to 5C and highs of 9 to 14C.

(A) The pure black morph is characteristic of Aneides niger and southern coastal populations of Aneides flavipunctatus, and this individual is from near Fort Bragg, Mendocino Co., CA. (B) The frosted morph is characteristic of Aneides klamathensis and can also be found in northern populations of Aneides flavipunctatus; this individual is from near Scotia, Humboldt Co. CA (population 14 in Fig. 2). (C) The spotted morph is characteristic of Aneides iecanus (although with smaller and more numerous spots than in this specimen) and southern inland populations of Aneides flavipunctatus; this individual was found near Boonville, Mendocino Co., CA. All of these salamanders are from the range of the revised A. flavipunctatus, illustrating the high degree of color pattern variation present within the species (photo: D Portik). — Representative image for context; not directly related to the specific event in this article. License: CC BY-SA 4.0. Source: Wikimedia Commons.

A sharp diurnal temperature spread is likely, particularly inland, where morning temperatures may dip below freezing and the day-night difference could reach about 15C. Frost is expected in parts of the inland south during the predawn hours.

Coastal areas should monitor sea conditions, as strong swells may flow toward the East Coast and Jeju Island. Local authorities may issue safety warnings for coastal and fishing communities.

City-by-city forecast (morning low / daytime high): Seoul 3C / 12C; Incheon 3C / 10C; Suwon 2C / 12C; Chuncheon -2C / 13C; Gangneung 2C / 12C; Cheongju 2C / 13C; Daejeon 1C / 14C; Jeonju 1C / 13C; Gwangju 1C / 15C; Daegu 0C / 15C; Busan 4C / 13C; Jeju 6C / 13C.

This figure shows the 30-year (1991-2020) average surface temperature (2m) for summer (DJF) and winter (JJA) in Antarctica based in ERA5 reanalysis data. — Representative image for context; not directly related to the specific event in this article. License: CC BY-SA 4.0. Source: Wikimedia Commons.

Why this matters for the United States: Korea is a major producer of high-tech components and a key node in global supply chains for semiconductors and electronics. Weather-driven risks—such as frost damage to agriculture, sharp temperature swings that affect energy demand, and coastal swells that can disrupt shipping and fishing—can ripple through regional markets and logistics. U.S. manufacturers and exporters that rely on Korean factories, ports, or components may monitor these conditions for risk management and scheduling.

Context for non-Korean readers: The forecast comes from the Korea Meteorological Administration (KMA), the national weather agency. Seoul is the capital and largest city; Busan is a major port on the southern coast; Jeju is a large island off Korea’s southern coast and a popular tourist destination. The East Sea, on Korea’s eastern coast, is known internationally as the Sea of Japan in some maps. Early-spring conditions in Korea often feature large day-to-night temperature differences and occasional frost in inland areas, with coastal areas more exposed to winds and swells.

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