Heatwave advisories have been issued for much of the western port city of Incheon as well as Gimpo, Bucheon and Siheung cities in Gyeonggi Province.
The Ministry of the Interior and Safety and the Korea Meteorological Administration issued the advisories at 11 a.m. Wednesday.
A heatwave warning is currently in place for some inland areas in the central region, including Seoul and parts of Gangwon Province. Meanwhile, a heatwave warning for the southern regions was lifted late Tuesday afternoon.
An advisory is issued when afternoon highs of 33 degrees Celsius or higher are forecast to continue for two consecutive days, while a heatwave warning is issued when daytime highs of 35 degrees and above are expected to continue for two days.