The cold spell will continue across the entire country after a morning low in Seoul on Friday below -10 degrees Celsius, according to the Korea Meteorological Administration.
Thursday saw -10.4 degrees in the capital.
This prolonged cold snap is caused by cold continental high pressure combined with a radiant cooling effect.
Temperatures in Seoul will remain below zero all day on Friday with the daytime high going up to -1 degree. They will drop below -15 in some parts of the country, with Cheorwon and Daegwallyeong in Gangwon Province seeing the mercury drop to -17 and Paju in Gyeonggi Province to -15.
"It will get slightly warmer over the weekend, but cold weather will be back from Monday, with Seoul’s morning low dropping to -10 degrees," a weatherman said.