Following the 20th, which is Daehan (the coldest period), a severe cold wave will continue nationwide on the 21st. The cold northwesterly wind will overlap, and the cold snap is expected to peak. Heavy snow is forecast for the southern regions, so commuters and drivers should take care on the roads.
According to the Korea Meteorological Administration, morning lows on the 21st will range from -17 to -4 C, with daytime highs from -7 to 3 C. In Seoul, the morning low is forecast at -13 C, with the wind chill expected to drop to -20 C. In most regions, temperatures will stay below 0 C even during the day, keeping the cold in place.
Cold air descending from Siberia is expected to meet the relatively warm Yellow Sea, forming snow clouds due to the air-sea temperature difference. Snow will concentrate along the Jeolla west coast and Jeju Island, starting early on the 21st and expanding to inland central Gwangju and South Jeolla and inland southern North Jeolla, continuing through the 22nd.
Expected snowfall: ▲ Five West Sea Islands 1–3 cm ▲ Southern Chungnam west coast around 1 cm ▲ North and South Jeolla west coast 3–10 cm ▲ Inland central Gwangju and South Jeolla, inland southern North Jeolla 1–5 cm ▲ Ulleungdo and Dokdo 10–30 cm ▲ Jeju mountains 5–15 cm (20 cm or more in some areas) ▲ Mid-mountain areas of Jeju 5–10 cm ▲ Jeju coast 3–8 cm.
In South Jeolla, Ulleungdo and Dokdo, and Jeju, heavy snow of up to 3 cm per hour is expected, so advance preparations are needed to prevent collapses of structures such as vinyl greenhouses. As accumulated snow may freeze and raise the risk of traffic accidents, extra caution is required.
At sea, strong winds and high waves are also expected. Winds will blow strongly at 30–65 kph, with waves of 1.5–4 meters, reaching over 5 meters in offshore waters. Vessels navigating or operating should pay close attention to safety.