Cool, dry air from a continental high-pressure system is bringing sunny days, low fine dust and unusually sharp visibility to central Korea through the weekend.
Clear skies stretch over the National Museum of Korea in Yongsan District, central Seoul, on Sept. 7.NEWS1
Cool mornings, warm afternoons and crystal-clear skies are giving central Korea a taste of classic autumn weather, with temperatures dipping as low as 11 degrees Celsius (52 degrees Fahrenheit) on Tuesday.
Seoul recorded a morning low of 17.8 degrees, below the seasonal average of 19.1 degrees, according to the Korea Meteorological Administration (KMA). Morning temperatures have been gradually falling since dropping into the teens over the weekend. Icheon, Gyeonggi, recorded 13.9 degrees, while Cheorwon, Gangwon, fell to 11.6 degrees.
But plenty of sunshine is expected to push daytime temperatures more than 10 degrees above the morning lows. Seoul is forecast to reach 30 degrees in the afternoon.
The cloudless skies have also brought exceptionally clear views. Visibility in Seoul reached 30.2 kilometers (18.8 miles) as of 9 a.m. on Tuesday. The previous morning, visibility exceeded 40 kilometers in parts of the capital, roughly the distance from central Seoul to Incheon Bridge in Incheon.
The crisp autumn conditions are being driven by a continental high-pressure system expanding from northern China. Cold, dry air descending from the north has lowered temperatures while reducing water vapor and fine dust that can obscure the atmosphere, resulting in greater visibility.
Seoul's concentration of ultrafine particulate matter, or PM2.5, briefly fell to just 1 microgram per cubic meter on Tuesday and remained in the “good” range of zero to 15 micrograms per cubic meter.
“Korea is sitting on the edge of a high-pressure system, allowing cool, dense air from the north to descend into the lower atmosphere,” Woo Jin-kyu, a forecaster at the KMA, said. “Clouds form when air rises and condenses, but the air is currently sinking, making it difficult for clouds to develop.”
Satellite imagery from the KMA's Chollian-2A weather satellite showed almost no clouds over the Korean Peninsula on Tuesday.
A satellite image from the Korea Meteorological Administration’s Chollian-2A satellite shows clear, cloudless skies over the Korean Peninsula on the morning of Sept. 8, in contrast to cloud-covered Japan.KOREA METEOROLOGICAL ADMINISTRATION
Japan, by contrast, has been hit by record rainfall due to an autumn rain front and Typhoon Krovanh, the season's 24th typhoon, which has weakened into a tropical depression.
Mostly sunny and pleasant autumn weather is expected to continue in Seoul through the weekend.
In Seoul, cloud cover is expected to push the morning temperature up to 20 degrees on Sept. 20 before lows fall back to around 16 degrees afterward. Afternoon temperatures are forecast to reach 26 to 27 degrees.
“The current weather pattern is expected to persist until around the weekend, when a high-pressure system from the northwest moves toward Korea, develops into a migratory high-pressure system and brings westerly winds,” Woo said.
This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.
