Morning temperatures in Seoul stood at -7.1 degrees Celsius on average for the first 10 days of December, the coldest in 56 years and the sixth coldest since 1907, when meteorological observation began.
According to the Korea Meteorological Administration, the morning low was below -10 degrees for four days, and the average in the capital on Dec. 1-10 this year was the same as a century ago in 1912.
Early December 1944 was the coldest with an average morning low of -10.4 degrees, followed by 1910 (-8.8 degrees), 1956 (-8.5 degrees), 1926 (-8.3 degrees), and 1937 (-7.2 degrees).
The cold snap affected the whole central part of the country. In early December, the average morning low in Chuncheon was -10.8 degrees, the lowest since 1966. Daejeon also saw the morning low plunge to -6.4 degrees, the coldest since 1969.
A KMA weatherman said, "In general, late January is the coldest time of the year, but in early December this year the mercury dropped to similar levels as late January or even lower."
The freezing temperatures are due to a huge cold air mass that developed 5 km above Siberia. "The air mass is gradually moving east, so the cold snap will ease from Friday or Saturday," a weatherman said.
The KMA forecast that the morning low in Seoul would rise to -1 degrees on Friday and 3 degrees on Saturday.