Children are playing in a fountain at Gwanghwamun Plaza in Seoul on Aug. 23. (Yonhap)

This year marked the longest streak of tropical nights in South Korea's recorded history, with regions across the country averaging 20.2 tropical nights so far, the state-run weather agency said Sunday.

The total number of tropical nights this year surpassed 16.8 in 1994 and 16.7 in 2018 -- years that are infamous among residents for being among the hottest years, according to the Korea Meteorological Administration. An average of 11.3 tropical nights was recorded in the month of August, marking the first time the monthly figure rose to the double digits since the country started tallying the phenomenon in 1973.

Tropical nights refer to when the lowest temperature between 6:01 p.m. and 9 a.m. the next day remains above 25 degrees Celsius, leading to uncomfortably hot, sleepless nights when combined with the high summer humidity.

Despite the heat subsiding in recent days, the KMA said an apparent temperature of 33 degrees Celsius is expected at least until Sept. 15.

Several regions across the country set new records for the number of tropical nights in a row, including 37 days for Seoul and a whopping 47 days for Jeju Island.

This year's August heat wave is likely to go down in history with the average temperature (Aug. 1-30) recorded at 28 degrees, marking an all-time high. The previous record for the same period was 27.2 degrees in 2018.

This August also set a new all-time high for the average temperature during the day and the average lowest temperature across the country: 33 degrees and 24.2 degrees, respectively.

Korea defines "heat wave days" as when the daily high is 33 degrees or higher. Both Seoul and Incheon have issued heat wave advisories for 38 consecutive days this year.

The scorching heat of 2024 has resulted in the third most heat wave days ever, when taking the average across the country, marking 23.2 days, following 31 in 2018 and 29.6 in 1994. The 16 heat wave days in August this year was second only to the same month in 2016, when the average temperature during the day was 33 degrees or above for 16.6 days across the country.

Of the 66 regions where the KMA has set up an observation point, 13 of them have reached new records for the average daily high temperature in August.

While it has begun transitioning into autumn, the relentless heat has been continuing on the peninsula. The average temperature for Seoul -- the country's capital and most populous city -- has stayed above 28 degrees for four days straight from Wednesday to Saturday, and the average temperature during the day for the region dipped below 28 degrees only once last week.

For comparison, the average temperature during the day for the last week of August 2018 was between 22.7 degrees and 25.6 degrees, possibly indicating that Korea has yet to witness the end of what has been one of the hottest periods in its recorded history.