End of 4 distinct seasons in Korea? Rising temperatures strengthen subtropical climate characteristics

A child cools off while playing in the fountains at Gwanghwamun Square in central Seoul, Monday, as the daytime high reached 32 degrees Celsius. Yonhap

Korea could become almost entirely subtropical by the end of the 21st century, according to a new warning from the Korea Meteorological Administration (KMA).

The findings were released Tuesday through an analysis by the KMA, which looked into the current status and future outlook of subtropical climate characteristics in the country. Using observational data — including average temperatures and precipitation — from 66 weather stations nationwide between 1981 and 2025, the agency projected how Korea's climate is likely to change in the coming decades.

The analysis found that temperatures in Korea have risen steadily. Over the past 53 years (1973–2025), the country's annual average temperature has increased by 0.3 degrees Celsius per decade. Last year, the national annual average temperature reached 13.7 degrees Celsius, the second-highest on record. The warming trend was especially pronounced during the transitional seasons, with February, March, September and November experiencing larger increases than other months.

As temperatures continue to rise, Korea's climate is gradually shifting from temperate to subtropical. A subtropical climate is defined as one in which the coldest month's average temperature remains below 18 degrees Celsius, while at least eight months of the year have average temperatures above 10 degrees Celsius. At present, about 80 percent of the country is still classified as temperate, with only seven months — April through October — averaging above 10 degrees Celsius.

However, when climate data are analyzed over 30-year periods, 14 regions — including Mokpo and Wando in South Jeolla Province, Tongyeong and Geoje in South Gyeongsang Province and Jeju — already exhibit subtropical climate characteristics. Looking at more recent 10-year periods, cities such as Gwangju, Uljin in North Gyeongsang Province and Gangneung on the east coast also qualify as subtropical.

"The number of regions where the average temperature in November exceeds 10 degrees Celsius has increased, indicating that subtropical climate characteristics have expanded northward into inland South Jeolla and the east coast," the KMA said.

The agency projects that if the world continues along a high-carbon emissions scenario without substantial reductions in greenhouse gas emissions, most of Korea — except for the inland western part of Gangwon Province — will become subtropical during the late 21st century (2081–2100).

Employees from the Buk District Public Health Center inspect emergency medications and medical equipment inside an ambulance parked at a public park in Jungheung-dong, Buk District, Gwangju, Tuesday, preparing to respond to heat-related illnesses. Yonhap

Far-reaching impact of climate shift

A shift to a subtropical climate means far more than simply hotter weather. The country's traditionally distinct four seasons would become less pronounced, while more frequent and more intense torrential downpours could occur. Ecosystems would also undergo significant changes, affecting crop-growing regions, animal habitats, plant growth and marine life.

Palm trees, once largely confined to Jeju Island, could spread farther north. Meanwhile, fruits such as apples and peaches would become increasingly difficult to cultivate. In Korean waters, squid populations could decline, while subtropical species such as Japanese amberjack (yellowtail) become more common.

Unless meaningful action is taken both domestically and internationally to reduce carbon emissions, everyday life in Korea could be transformed.

Experts stressed the need to prepare for these changes. Koo Ja-ho, an atmospheric sciences professor at Yonsei University, argued that if Korea truly enters a subtropical climate zone, the country's entire approach to defining its seasons should be reconsidered.

"Rather than dividing the year into four equal three-month seasons, we should redefine the seasons based on actual meteorological, climatic and environmental characteristics," he said.

Citizens take refuge from the heat inside a cooling shelter installed at Gwanghwamun Square in central Seoul, June 10. The Seoul Metropolitan Government is operating air dome-style cooling shelters to provide relief from extreme heat. Equipped with chairs, air conditioners and fans, the shelters offer visitors a place to rest and cool down. Yonhap

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