By Ian Werther in News — 14 Mar 2026

South Korea Weekend Forecast: Frost, Fog, and Rough Seas Could Disrupt U.S. Supply Chains

A nationwide weekend forecast in South Korea calls for cool, unsettled conditions with a pronounced daily temperature swing. On Saturday, skies are expected to be mostly cloudy, with chilly mornings and temperatures climbing into the low to mid-teens by afternoon. Inland areas are likely to see morning temperatures fall below freezing, with frost possible in parts of the Chungcheong inland and the southern inland regions.

Daytime highs are forecast to range from about 10°C to 15°C. In major cities, the expected daytime temperatures are: Seoul and Suwon around 12°C, Incheon 10°C, Gangneung, Sejong, Busan and Jeju about 13°C, Daejeon 14°C, and Gwangju and Daegu near 15°C. Sunday is expected to repeat the pattern, with morning frost and similar daytime highs, keeping the daily temperature swing large and temperatures near seasonal norms.

Assorted diatoms as seen through a microscope. These specimens were living between crystals of annual sea ice in McMurdo Sound, Antarctica. Image digitized from original 35mm Ektachrome slide. These tiny phytoplankton are encased within a silicate cell wall. — Representative image for context; not directly related to the specific event in this article. License: Public domain. Source: Wikimedia Commons.

Regionally, the central parts of the country are expected to be mostly cloudy, while southern regions may see intermittent cloud cover; Jeju Island should be generally clearer. In southern inland areas, fog is possible through the morning, with visibility dropping to under 1 kilometer in some spots. Fog could be denser near rivers, lakes and valleys, so drivers should take extra care.

Maritime conditions will be unsettled. Winds are forecast at 30 to 60 kilometers per hour in waters off the southern eastern coasts and around Jeju, with the strongest winds likely through the morning and into the afternoon in parts of those zones. Swell may bring large waves to the East Sea coastal waters and around Jeju, highlighting potential hazards for coastal and maritime activity.

Envisat captures dust and sand from the Algerian Sahara Desert, located in northern Africa, blowing west across the Atlantic Ocean. Sandstorms are very common over the Sahara, and large concentrations of the dust can be found in the tropical Atlantic and the Caribbean. The dust contains many nutrients, including nitrogen, phosphorus and iron, which act as a fertiliser and stimulate the production of massive plankton blooms. In this image, plankton blooms are visible in the Atlantic as blue and green swirls.
Although some types of plankton are individually microscopic, the chlorophyll they use for photosynthesis collectively tints the colour of the surrounding ocean waters. This allows dedicated 'ocean colour' satellite sensors, such as Envisat's Medium Resolution Imaging Spectrometer (MERIS), to detect them from space. MERIS acquired this image on 8 April 2011 at a resolution of 300 m. — Representative image for context; not directly related to the specific event in this article. License: CC BY-SA 3.0 igo. Source: Wikimedia Commons.

Air quality is expected to be favorable, with fine particulate matter in the good to moderate range across most of the country.

Why this matters to the United States: South Korea is a key player in global manufacturing and electronics supply chains, as well as a major exporter of autos and other high-tech goods. Frost and fog can disrupt agricultural output and domestic transport, while rough seas and high winds affect port operations, shipping schedules and logistics that feed into global markets. For U.S. companies and consumers, weekend weather in Korea can influence manufacturing timelines, overseas shipments, and the availability of consumer electronics and autos sourced from the region. Understanding these conditions helps gauge potential ripple effects on supply chains and markets.

Subscribe to Journal of Korea