The weather agency said it will upgrade its cold wave advisory to a cold wave warning from 9 p.m. Tuesday. 

Such an advisory is currently in place for Seoul, Incheon and 24 areas in Gyeonggi Province, the Chungcheong Provinces, Gangwon Province and parts of Sejong City. 

Also from 9 p.m. Tuesday, a cold snap warning will be issued for most parts of the nation excluding some regions along the nation's east coast.

A cold wave warning is issued when morning lows plunge more than 15 degrees Celsius from the previous day to under three degrees and are at least three degrees lower than the average year or when morning lows remain below minus 15 degrees for more than two days. 

A cold wave advisory is issued when morning lows dive more than ten degrees from the previous day to under three degrees and are at least three degrees lower than the average year or when morning lows continue to stand at minus 12 degrees or lower for more than two days. 

The government advises the elderly to refrain from going outside and take care of their health.