![Spring equinox, clear weather with large temperature difference between day and night...watch for early morning fog [Today's Weather] - Seoul Economic Daily Culture News from South Korea](https://wimg.sedaily.com/news/cms/2026/03/19/news-p.v1.20260319.bcf13ffa0eeb4dcea3517bde1175fd26_P1.jpg "Spring Equinox Brings Clear Skies, Wide Temperature Swings")
Friday, March 21, marks the spring equinox—when day and night are equal in length—and clear skies are forecast nationwide.
However, fog is expected in inland areas from tonight through tomorrow morning.
Morning lows will range from -4 to 6 degrees Celsius, with afternoon highs of 11 to 17 degrees Celsius.
The significant temperature gap between day and night is expected to continue for the time being. With early morning temperatures dropping low enough for frost, farmers should take precautions to protect their crops.
Fine dust levels are forecast to remain between "good" and "moderate" across all regions.
Wave heights in coastal waters are expected to reach 0.5 to 2.0 meters in the East Sea and 0.5 to 1.0 meters in the West and South Seas. Offshore waters within approximately 200 kilometers of the coastline will see waves of 0.5 to 3.5 meters in the East Sea and 0.5 to 1.5 meters in the West and South Seas.
