This weekend will keep temperatures near normal, with the temperature gap between day and night widening to 10–15 degrees, mainly inland.
On Saturday the 12th, Korea will be under the influence of a high-pressure system moving from northeastern China to the northern East Sea, and on Sunday the 13th, it will lie on the edge of the high that has shifted over the East Sea.
Because of cold air sinking south along the high, the weekend will be generally cool.
However, with radiative cooling overnight, mornings on the 12th will feel somewhat chilly in central regions and the southern interior compared with this time of year.
On the morning of the 12th, lows will be 12–20 degrees, with afternoon highs of 25–30 degrees.
Forecast lows and highs for major cities are Seoul 17 and 28, Incheon 18 and 27, Daejeon 15 and 27, Gwangju 18 and 30, Daegu 16 and 29, Ulsan 17 and 27, and Busan 20 and 29.
On the 13th, morning lows are expected to be 13–21 degrees, with afternoon highs of 23–31 degrees.
Most areas will see intervals of many clouds over the weekend. However, as these are high clouds formed by the jet stream passing through the upper atmosphere over Korea, strong sunshine will come through between clouds during the day.
As daytime temperatures rise, the difference between day and night will widen to 10–15 degrees, mainly inland.
As sunlight triggers photochemical reactions of air pollutants and generates ozone, ozone concentrations will reach the "bad" level for a time in the afternoon in the capital area, South Chungcheong, and South Jeolla on the 12th, and in South Jeolla, Busan, and South Gyeongsang on the 13th.
The capital area and Gangwon will be cloudy through the morning of the 13th, and raindrops are possible in the capital area excluding southern Gyeonggi and in central and northern Gangwon. Under the influence of easterly winds, 5–10 mm of rain will fall in the Jeju highlands from the afternoon to night on the 13th.