As of 8 a.m. the lowest temperature in Seoul was minus 10.2 degrees Celsius and the lowest apparent temperature minus 16.7 degrees Celsius, according to the Korea Meteorological Administration (KMA).

A cold wave advisory took effect for all of Seoul at 9 p.m. the previous day. An advisory is issued when a morning low of minus 12 degrees Celsius or less is expected for two or more consecutive days.

The lowest temperatures in other regions ranged from minus 16.9 degrees Celsius in the Daegwallyeong mountain pass in Gangwon Province to minus 13.6 degrees Celsius in Cheorwon and minus 13 degrees Celsius in Cheonan.

Further south, temperatures fell to as low as minus 6.8 degrees Celsius in Gwangju, minus 6.1 degrees Celsius in Ulsan and minus 4.7 degrees Celsius in Busan.

"The temperature fell below minus 20 degrees Celsius in parts of the mountainous regions of Gangwon, while in the central region, the eastern area of North Jeolla Province and the northern inlands of North Gyeongsang Province, it ranged from minus 15 degrees Celsius to minus 10 degrees Celsius, and in the rest of the country it fell to minus 5 degrees Celsius," the KMA said.

"Many parts of the country recorded their lowest temperatures of this winter," it added.

The cold snap is expected to continue for some time, with Thursday's daily high forecast to range from 3 degrees Celsius to 11 degrees Celsius and most of the country seeing subzero temperatures all day.

The South Chungcheong and Jeolla provinces, as well as the mountainous areas of Jeju Island, are forecast to receive snow for the fourth consecutive day, with up to 5 centimetres of snow per hour at times.