Dense inland fog and rising early-summer temperatures affected South Korea on Wednesday, May 13, 2026.
The sudden shift in weather conditions created hazardous driving environments during the morning commute while signaling an accelerated transition into summer heat.
Weather authorities reported that visibility fell to less than 200 meters [1] in inland regions, specifically impacting areas around Seoul, Daejeon, and Daegu [1, 2]. The fog developed after recent rainfall increased humidity levels across the peninsula [1, 2].
Jung Su-hyun of YTN said drivers should maintain greater distances between vehicles than usual due to the low visibility [1]. Morning temperatures remained cool, with Seoul and Daegu both recording 13.4 degrees Celsius [1], while Daejeon was slightly warmer at 14.4 degrees Celsius [1].
Despite the morning chill, midday temperatures rose sharply. Seoul reached 26 degrees Celsius [1, 3], and Daegu climbed to 28 degrees Celsius [1]. These figures align with early-summer weather patterns for the region.
Forecasters expect the warming trend to intensify over the coming days. Temperatures are projected to exceed 30 degrees Celsius [1] by the weekend.
This combination of high humidity and rapid heating is typical for the transition into the summer monsoon season, though the intensity of the fog posed immediate risks to road safety in the interior provinces [1, 2].
“Visibility reduced to less than 200 meters in inland fog”
The rapid swing from dense morning fog to early-summer heat highlights the volatile atmospheric conditions South Korea faces during May. The intersection of high humidity from recent rains and seasonal heating creates a specific risk profile for inland transportation, requiring increased vigilance for commuters before the region enters its consistent summer heatwave cycle.
