By Ian Werther in News — 14 Mar 2026

South Korea Frost, Fog and Rough Seas Could Disrupt Ports and Shipments

South Korea is forecast to have a cloudy Saturday with a cold start and a milder afternoon. Inland areas are expected to fall below freezing in the morning, with daytime highs around 10 to 15 degrees Celsius. In major cities, daytime highs are projected as follows: about 12°C in Seoul, Suwon and Ulsan; 10°C in Incheon; 13°C in Gangneung, Sejong, Busan and Jeju; 14°C in Daejeon; and 15°C in Gwangju and Daegu.

Frost is anticipated mainly in inland parts of the Chungcheong region and southern inland areas, so farmers should monitor crops.

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.

The central regions are expected to be mostly cloudy, while the southern regions may have occasional cloudiness. Jeju Island is forecast to be largely clear. Inland areas in the south could experience fog, with visibility under 1 kilometer in some places through the morning.

Fog may become denser along roads near rivers, lakes and valleys, so drivers should exercise caution.

Maritime conditions will be rough in the morning, with winds of 30 to 60 kilometers per hour forecast for the southern East Sea, the southeastern part of the South Sea, and the inner waters to the southeast of Jeju. Winds in Jeju’s southern outer waters are expected to remain strong through the afternoon. Swells are likely to bring strong waves along the East Coast and around Jeju, potentially affecting coastal boating and shipping.

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.

Fine dust levels are expected to range from good to moderate nationwide.

Why this matters beyond Korea: weather conditions like frost, fog, and rough seas can disrupt logistics and transportation that connect Korea to global supply chains. South Korea’s ports, including Busan and Incheon, are major hubs for manufactured goods such as electronics and automobiles; disruptions to port operations or inland transport can ripple through regional and global markets. For U.S. companies, weekend forecasts that foresee fog, frost, or heavy seas may influence scheduling, inventories, and the timing of shipments to or from Northeast Asia. The forecast also highlights how agricultural production can be affected by cold mornings and frost risk in inland areas, with potential implications for food and commodity markets.

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