People enjoy a weekend outing at Sky Park in Mapo-gu, Seoul, on September 22, which saw unseasonably mild early autumn weather across the country. The day falls on the autumnal equinox, when the length of day and night are equalised.
SEOUL & YEOJU, Sept. 23 (Korea Bizwire) – The Korea Meteorological Administration (KMA) reported on September 22 that the late summer heat wave has finally subsided across the country, following weekend rains that brought relief from sweltering temperatures and tropical nights.
On the morning of September 21, most regions in South Korea, including Seoul, experienced temperatures below 25 degrees Celsius. Jeju Island, which had endured 75 consecutive days of tropical nights — defined as nights with minimum temperatures above 25°C — saw the streak end as temperatures dipped to 23.4°C between the night of September 21 and early morning of September 22.
“With the late summer heat dissipating, we expect temperatures to remain close to or slightly above the seasonal average in the coming days,” a KMA official stated. The official added that typical autumn weather patterns are emerging, characterized by cooler mornings and evenings, resulting in significant daily temperature fluctuations.
The sudden arrival of autumn-like conditions is attributed to a shift in the atmospheric pressure systems over the Korean Peninsula.
The KMA explained that the Tibet high-pressure system and the North Pacific high-pressure system, which had blanketed the region and caused record-breaking summer heat, have now retreated. This retreat has created a pathway for cooler, drier air from the north to move southward.
A variety of plants give off an autumnal atmosphere at Dangnamriseom Island in Yeoju, Gyeonggi-do, on September 22, the autumnal equinox. From top, yellow cosmos, pink mulleys, cosmos, and mugwort.
Gong Sang-min, a forecast analyst at the KMA, noted, “Cool, dry air from the north will linger over the central regions for the time being, leading to generally clear weather.”
He added that daily temperature variations could reach around 10°C in most parts of the country, except for Jeju and some southern areas not yet affected by the cooler air mass.
The KMA predicts that morning temperatures will drop to around 15°C in central regions and southern inland areas on September 23 and 24.
Daytime highs are expected to range from 22°C to 29°C. However, the KMA assures that no regions will experience temperatures exceeding 30°C.
Despite the cooler temperatures, the official start of autumn, as recognized by the KMA, is likely to be delayed this year.
The agency defines the start of autumn as the first day when the average daily temperature falls below 20°C and does not rise above that threshold again.
Based on recent averages (2011-2020), autumn typically begins in Seoul on September 29. However, a KMA representative stated, “Due to the persistence of late summer heat this year, we anticipate the start of autumn to be later than usual.”
Image credit: Yonhap / photonews@koreabizwire.com
