A child cools off at a floor fountain amid sweltering heat in a park in Gwangju City, Aug 2. Yonhap

This summer, Korea experienced its highest average temperature since nationwide weather observations began in 1973, with the average temperature reaching 25.6 degrees Celsius, according to the weather agency, Thursday.

The number of tropical nights also surged to more than three times the normal level, setting a new record.

According to the Korea Meteorological Administration's "2024 Summer (June to August) Climate Characteristics" report, this summer was characterized by high temperatures, frequent tropical nights, intense rainfall during the monsoon season, and sparse precipitation after late July.

The national average temperature this summer was 25.6 degrees Celsius, 1.9 degrees higher than the normal average of 23.7 degrees.

This surpassed the previous record of 25.3 degrees Celsius set in 2018, which was known for its "extreme heatwave."

Contributing factors included the persistent influx of hot and humid southwesterly winds and the overlapping effects of the Tibetan High and North Pacific High over the Korean Peninsula from late July to late August. This combination led to clear skies and intense solar radiation. Notably, the average temperature in August was 2.8 degrees Celsius higher than usual.

Citizens take a break at Cheonggye Stream in Seoul amid tropical nights on Aug. 24 . This summer, Seoul experienced 39 tropical nights, setting a new record for the highest number of such occurrences. Newsis

Severe tropical nights

This summer was characterized not only by intense heat waves with daily high temperatures exceeding 33 degrees Celsius but also by severe tropical nights, where the minimum temperature remained above 25 degrees Celsius.

The nationwide average for heatwave occurrences this summer was 24 days, the third highest on record and 2.3 times greater than the usual average of 10.6 days.

The highest number of heatwave days on record was 31 in 2018, followed by 28.5 days in 1994. This year, the number of tropical nights reached a record-breaking 20.2 days, which is 3.1 times the average of 6.5 days. This figure far exceeds the 16.5 days recorded in both 2018 and 1994.

Regionally, 36 out of 66 major weather observation sites across the country set new records for the number of tropical nights this year.

Notably, Jeju recorded 56 tropical nights, Yeosu 42, Seoul 39, and Incheon 36, with all experiencing over a month of such nights. Additionally, the number of sweltering days set new records at 10 out of 66 locations.

The summer sea surface temperature around the Korean Peninsula reached 23.9 degrees Celsius, 1.1 degrees higher than the recent 10-year average (22.8 degrees from 2015 to 2024), marking the highest level in the past decade.

Firefighters rescue an employee stranded in a flooded factory in Wollong-myeon, Paju, Gyeonggi Province, on July 18. This summer's rainfall was marked by intense downpours concentrated in narrow areas during the monsoon season. In Paju, Gyeonggi Province, a maximum of 101 millimeters of rain fell per hour on July 17. Yonhap

Rainfall below average

This summer's rainfall was below average, with most of it concentrated during the monsoon season. The national average rainfall was 602.7 millimeters, which is 82.5 percent of the normal average of 727.3 millimeters.

Typically, about half of the summer rain falls during the monsoon period. But this year, 78.8 percent (474.8 millimeters) of the summer rainfall was concentrated during the monsoon season — the highest proportion since 1973. Outside the monsoon period, there were many clear days, resulting in less rainfall.

The monsoon season this year was particularly characterized by intense downpours concentrated in narrow areas.

There were nine instances where the maximum hourly rainfall exceeded 100 millimeters. Typically, an hourly rainfall of over 20 millimeters is classified as "heavy rain." Therefore, experiencing a single day's rainfall equivalent to the entire month's average for spring (118.4 millimeters in May this year) highlights the extreme intensity of the downpours.

A digital billboard at Jamsil Intersection in Songpa District, Seoul, displays a temperature of 34 degrees Celsius on Aug. 20. Seoul experienced an unrelenting heatwave, recording a month of consecutive tropical nights in August for the first time in history. Yonhap

This article from the Hankook Ilbo, a sister publication of The Korea Times, is translated by a generative AI and edited by The Korea Times.