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Get your masks ready: Warmer but smoggier weather forecast for Seoul area this week

Published: 15 Dec. 2025, 23:27

Fine dust pollution shrouds Seoul as seen from the Seoul Metropolitan Office of Education in Jongno District, central Seoul, on Dec. 7. [YONHAP]

Korea will see a break from subzero temperatures this week, but residents of the greater Seoul area should brace for several days of hazy skies due to elevated fine dust levels, officials said on Monday.

Temperatures across Korea will rise above seasonal averages from Tuesday as a cold air mass that drove readings below freezing weakens, the Korea Meteorological Administration (KMA) said.

Seoul’s morning low will rise to 3 degrees Celsius (37.4 degrees Fahrenheit), more than 6 degrees higher than the previous day’s minus 3.5 degrees. Morning temperatures in the capital are expected to remain around zero degrees Celsius through the end of the week, with no severe cold spells forecast.

As temperatures climb, however, air quality across the greater Seoul area is expected to deteriorate. Pollutants flowing in from China across the Yellow Sea will combine with domestically generated emissions as calmer conditions prevent dispersion.

"Some central and western regions will see a buildup of locally generated particulate matter in the morning on Tuesday, followed by an inflow of overseas pollutants carried by northwesterly winds from the evening, pushing concentrations higher," the air quality forecast center at the National Institute of Environmental Research (NIER) said.

Seoul and southern Gyeonggi are expected to record “bad” levels of fine dust on Tuesday.

Ultrafine dust, composed of airborne particles measuring 2.5 microns or less in diameter (PM 2.5), can penetrate deep into the lungs and pose health risks when concentrations are high. “Bad” levels of ultrafine dust are defined as concentrations between 36 and 75 micrograms per cubic meter.

Other parts of the greater capital area, including Incheon, as well as much of the Chungcheong provinces, are forecast to see PM2.5 levels worsen to “bad” overnight. Light rain of about 1 millimeter is expected in the capital region from early morning to morning on Tuesday, though officials said it would not be sufficient to clear the pollution.

Citizens run along a coastal road in Buk District, Pohang, North Gyeongsang, on Dec. 10, as fine dust levels in the area reached around 60 micrograms per cubic meter. [NEWS1]

Elevated particulate levels are likely to persist after Wednesday as polluted air continues to arrive from China and stagnant conditions linger, preventing pollutants from dispersing. Forecasts show high PM2.5 concentrations in Seoul, Incheon and southern Gyeonggi through Friday. Conditions are expected to improve over the weekend as cleaner southerly winds move in and snow or rain falls across central regions.

Such spikes in fine dust levels when cold weather eases, turning the sky hazy, are a common wintertime phenomenon. High-pressure systems settling around the Korean Peninsula can weaken winds and cause stagnant air conditions, while pollutants flow in from across the Yellow Sea, allowing fine dust to accumulate.

The NIER's air quality forecast center said such episodes may occur more frequently this winter than last. It estimated a 50 percent chance that the number of days with nationwide PM2.5 concentrations at “bad” levels or worse will exceed last winter’s total, compared to a 30 percent chance of similar levels and a 20 percent chance of fewer days.

Even so, officials said the total number of polluted days is likely to remain below the seasonal average.

"High-pressure circulation around Korea is expected to strengthen during the winter period, increasing the likelihood of stagnant air,” said an official at the NIER's air quality forecast center. "When concentrations rise, people should wear masks outdoors and limit prolonged or strenuous outdoor activities.”

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.
BY CHON KWON-PIL [[email protected]]