Weather Forecast: Cool Mornings and 30-Degree Days Ahead

By Inhyeok Choe Posted : September 20, 2026, 18:00 Updated : September 20, 2026, 18:00

On Monday, the 21st, clear skies are expected nationwide, with daytime temperatures rising to a high of 31 degrees Celsius, indicating a significant temperature difference throughout the day.


According to the Korea Meteorological Administration, the morning low on the 21st is forecasted to be between 11 and 19 degrees Celsius, while the daytime high will range from 24 to 31 degrees. The morning lows are similar to the average (12-19 degrees), but the daytime highs exceed the typical range (23-27 degrees).


In Seoul, the morning will be cool, but temperatures are expected to reach up to 30 degrees during the day. The expected daytime highs for major cities include Gwangju at 30 degrees, Incheon, Cheongju, Daejeon, and Jeonju at 29 degrees, Suwon, Chuncheon, Wonju, Sejong, and Daegu at 28 degrees, Busan at 27 degrees, Ulsan and Jeju at 26 degrees, and Gangneung at 25 degrees. Most regions will experience a temperature difference of over 10 degrees between day and night, necessitating careful health management during this transitional season.


The skies will generally be clear across the country, although the eastern coast of Gangwon, mountainous areas, and the eastern coast of Gyeongsang Province, as well as Jeju Island, may see occasional clouds. Light rain, less than 0.1 mm, may fall in some areas of the eastern coast and mountainous regions of Gangwon during the night.


There is also an increased risk of safety incidents at sea and along coastlines. Strong winds and high waves are expected in the southern offshore waters and around Jeju Island, with a high likelihood of a storm warning being issued. For the time being, strong swells along the eastern coast, southern coast of Gyeongnam, and Jeju Island may reach beaches, rocky shores, and breakwaters, requiring caution from beachgoers and visitors to coastal areas.





* This article has been translated by AI.

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