Thick fog is set to hit inland and west coast areas from dawn to morning on the 24th, with visibility falling to less than 200m in some places just as the Chuseok holiday begins. Roads, bridges and coastal routes are likely to feel the impact first, before rain spreads to more parts of the country later in the holiday.
That timing matters because many travelers will already be on the move before sunrise, and the first full holiday morning is when low visibility can turn a routine drive into a slower one. The full moon of Chuseok is expected to rise around 5:30 p.m., but thick cloud and fog mean many people will not get a clear view of it.
The fog will not be limited to a narrow strip of land. Visibility of less than 1km is expected on the west coast of Seoul, Incheon, Gyeonggi, inland of Gyeongbuk and inland of western Gyeongsangnam-do, while the West Sea Bridge and the Angel Bridge are also forecast to be foggy. In inland Gyeonggi, inland Gangwon, mountainous areas, Chungcheong and Honam, the haze is expected to be dense enough to cut visibility below 200m, a level that can sharply slow traffic and make lane changes more dangerous.
Rain follows behind that fog in a staggered pattern. Between late night on the 24th and morning on the 25th, showers will fall on the eastern coast and mountainous areas of northern Gangwon Province. In the late afternoon of the 25th, rain will begin in the central region, North Jeolla Province and North Gyeongsang Province, then continue in the central part of the country until early dawn on the 26th. Rain will then spread to the southern part of the country and Jeju on the 26th, stopping that day in the south while Jeju keeps getting rain into the next morning.
The weather is uncomfortable, but not especially cold. Temperatures on the 24th are expected to run from 14-19 degrees in the morning to 26-30 degrees in the day, and the next two days stay in a similar range, with highs of 23-28 degrees on the 25th and 24-28 degrees on the 26th. That leaves the holiday period near seasonal levels, or a little above them, even as clouds and rain reduce visibility and make the travel window less forgiving.
Precipitation through the 25th is expected to stay around 5mm or less in most areas, though the northeastern coast of Gangwon-do and mountainous areas may see 5-10mm. The bigger concern is not the amount of rain alone, but where it lands and when, especially for drivers trying to beat the fog early and the rain later in the holiday.
Sea conditions add another layer of caution. High waves are expected on the east coast from the night of the 24th to the 25th, and on the 26th gusts of wind, thunder and lightning are expected in the Namhae and Jeju seas. By the time the holiday reaches its middle and end, the main problem will not be a single storm but a rolling stretch of poor visibility, wet roads and rougher seas that keeps shifting from region to region.
