GK:1.3.5 Fog
Geography of Korea: I. Natural Environment > 3. Climate > 5) Fog
5) Fog
Fog frequently occurs in fall, with its large diurnal temperature range, as well as in the humid months of summer. The area of the peninsula with the highest occurrence of fog is at Daegwallyeong (a mountain pass in the Taebaeksanmaek Range of eastern South Korea), which has recorded more than 130 days of fog annually. Fog is particularly common at Daegwallyeong during the rainy season between June and September. Fog here is caused mainly by wet air coming off the East Sea that then forms clouds as it rises over the Taebaeksanmaek Range of mountains.
In fall, fog-prone locales like Suncheon and Jinju can also experience as many as 90 foggy days. Each of these two locations are situated adjacent to reservoirs—Lake Juam and Lake Jinyang, respectively—and are encircled by mountains. As a result, not only do these areas have abundant water vapor but cooler air flowing down from the nearby mountains as well as the naturally occurring radiative cooling of the earth’s surface, results in temperature inversion and frequent fog. Locations like Imsil, Chungju, and Andong have similar conditions to Suncheon and Jinju and also experience many foggy days. Cities such as Hongcheon, Yeongwol, Hapcheon, and Geumsan, situated near large rivers and surrounded by high mountains, are also very fog-prone.
In the southwest coastal region more than 60 percent of the fog days experienced annually are in the summer. In early summer, the group of islands between Heuksan-do and Jin-do Islands off the southwest coast of the peninsula frequently experience advection fog, a fog caused by a hot and humid wind blowing over relatively cool water. Meanwhile, in the northern portion of the peninsula, places like Unggi, Cheongjin, and Seongjin on the eastern coast experience frequent fog during June and July due to the influence of the cold North Korean current. Due sea fog’s relatively long persistence compared to ground inversion fog, it can interfere greatly with sea transport.
