Cool mornings, highs near 30 C this weekend as temperature swings widen

Temperatures this weekend are expected to remain near seasonal norms, with cool mornings giving way to warmer afternoons as sunshine pushes daytime highs up — widening the daily temperature gap, particularly inland.

According to Yonhap, South Korea will fall under the influence of a high-pressure system moving from northeastern China toward the northern East Sea on Saturday, then sit along the edge of that system as it shifts further out to sea on Sunday.

Cold air flowing southward along the high-pressure system will keep conditions generally cool throughout the weekend. Saturday morning in particular is forecast to feel somewhat chillier than usual for this time of year across central and southern inland areas.

Saturday's morning lows are expected to range from 12 to 20 degrees Celsius, with afternoon highs of 25 to 30 C. Forecast lows and highs for major cities are: Seoul 17 C and 28 C, Incheon 18 C and 27 C, Daejeon 15 C and 27 C, Gwangju 18 C and 30 C, Daegu 16 C and 29 C, Ulsan 17 C and 27 C, and Busan 20 C and 29 C.

On Sunday, morning lows are forecast between 13 and 21 C, with afternoon highs ranging from 23 to 31 C.

Skies will be partly cloudy across most of the country over the weekend, but strong sunshine breaking through the clouds during the day will push afternoon temperatures up considerably. Inland areas can expect a daily temperature swing of 10 to 15 C.

Sunlight triggering photochemical reactions with airborne pollutants will also generate elevated ozone levels. Concentrations are forecast to reach "poor" levels during the afternoon on Saturday in the Greater Seoul area, South Chungcheong Province and South Jeolla Province, and on Sunday in South Jeolla Province, Busan and South Gyeongsang Province.

The Greater Seoul area and Gangwon Province will see cloudy skies Sunday morning, with scattered raindrops possible across most of the metropolitan area — except southern Gyeonggi Province — and central and northern Gangwon. Easterly winds will bring 5 to 10 millimeters of rain to mountainous areas of Jeju on Sunday afternoon through the night.

The moon's gravitational pull will remain strong for now, keeping tidal levels elevated. Coastal low-lying areas are at risk of flooding during high tide, and residents are urged to take precautions.