South Korea has experienced a dramatic increase in extreme heat over the past century, with heat wave days doubling and tropical nights quadrupling compared to the early 1900s, according to a comprehensive climate analysis released Wednesday.
The Korea Meteorological Administration (KMA) published a report analyzing 113 years of climate change data from 1912 to 2024, the longest-period study of its kind for the country.
The report examined long-term climate changes in temperature, precipitation, and extreme weather indices at six observation sites including Incheon, Mokpo, Busan, and Seoul, where records date back to the early 1900s.
Heat wave days surged from 7.7 days in the 1910s to 13.3 days in the 2010s and 16.9 days in the 2020s—a 2.2-fold increase over approximately 110 years. Tropical nights rose even more sharply, from 6.7 days in the 1910s to 19.7 days in the 2010s and 28.0 days in the 2020s, representing a 4.2-fold increase.
Average annual temperatures have risen 0.21 degrees Celsius per decade, with the pace accelerating dramatically in recent years. While temperatures increased 1.9 degrees over the century from 12.0 degrees in the 1910s to 13.9 degrees in the 2010s, they jumped another 0.9 degrees in just one decade to reach 14.8 degrees in the 2020s.
Seven of the ten hottest years on record occurred within the past decade. The year 2024 ranked first at 15.4 degrees, followed by 2023 at 14.8 degrees and 2021 at 14.5 degrees.
"Recent summer temperature increases have intensified while winter temperature rises have slowed," the KMA said.
Heavy rainfall events have also become more frequent. While the number of rainy days decreased by 0.68 days per decade over the 113-year period, total annual precipitation increased by 17.83 millimeters per decade. Days with heavy rain and days with hourly precipitation exceeding 50 millimeters both increased by 0.08 and 0.04 days per decade, respectively.
"As climate change intensifies, the KMA will reform its heat wave and heavy rain response systems, including establishing new severe heat wave alerts and tropical night advisories, and expanding emergency text notifications for heavy rain," KMA Administrator Lee Mi-seon said.
