With heatwave alerts issued nationwide, Seoul, Gyeonggi Province and coastal regions, where tropical nights were reported, posted temperatures surpassing 30 degrees Celsius early Friday.
Daytime highs in Seoul and the eastern Gangwon city of Chuncheon are forecast to reach 37 degrees, while 36 degrees is expected in the southwestern city of Gwangju, 35 degrees in the central city of Daejeon, and 34 degrees in the southeastern city of Daegu.
Temperatures in western regions are on the rise amid incoming warm winds from a high pressure system in the North Pacific centered over the Korean Peninsula's east.
On top of that, the year's sixth typhoon, In-fa, traveling north from China's eastern coast, has been emitting heat throughout the week.
The Korea Meteorological Administration(KMA) forecast heat waves to continue for some time with hot vapors traveling towards the peninsula, despite the typhoon landing along China's south coast on Sunday.
Daytime highs in Seoul will likely peak at 37 degrees on Saturday, and stay at around 35 next week.