Seoul recorded its 24th consecutive tropical night, marking the second-longest streak since modern weather observations began in 1907.
With the heatwave expected to continue, the country is likely to break the record of 26 consecutive tropical nights by the end of the week.
The relentless heat has significantly impacted daily life in South Korea. Electricity demand has surged to an all-time high of 102.3 gigawatts as people rely heavily on air conditioning and fans to stay cool.
The intense heat has also led to the cancellation of several professional baseball games, a first in the league's 43-year history.
Many South Koreans are finding creative ways to cope with the heat. Public parks and streets are equipped with misting stations, and people are seen carrying portable fans and umbrellas for shade.
According to a producer in Seoul, Kim Sung-yoon, "I used to think I was quite tolerant of heat, but these days, I wake up two or three times during my sleep. It is so hot that I keep waking up, so it is hard to sleep. These days, getting a good night's sleep seems to be the hardest thing."
Director at Korea Medical Tour Development Inc., Kim Soon-hee also adds "Since people have already experienced this wonderful invention called 'air conditioning', they cannot help but use it to beat the heat. So it seems that the Earth will only get hotter and hotter."