🇰🇷South Korea

South Korea spans 33°06′–38°37′N, an East Asian country covering approximately 100,210 km² on the southern half of the Korean peninsula plus some 3,400 islands including Jeju, Ulleung, and Dokdo. The Taebaek Mountains dominate the east coast with Mount Seoraksan rising to 1,708 m, the Sobaek range branches southwest with Jirisan at 1,915 m marking the highest peak on the mainland, and the volcanic Halla-san on Jeju Island reaches 1,950 m as the country's overall highest peak.

This topography produces a strongly seasonal monsoon climate — humid continental (Dwa) in the north and interior including Seoul, humid subtropical (Cfa) on the southern coast and Jeju, and a subarctic-tinged (Dwb) tendency at high elevations — modulated by the cold dry winter northwest Siberian monsoon and the wet hot summer southeast monsoon plus the changma summer rainy front and typhoons.

Seoul averages −2°C in January and 26°C in August with 1,420 mm rainfall concentrated June–September; Busan on the south coast records 5°C January and 25°C August with 1,520 mm; Jeju registers 6°C and 27°C with 1,500 mm; Daegu in the southeast basin records 1°C and 26°C with 1,030 mm; Gangneung on the east coast registers 1°C and 24°C with 1,400 mm and heavy winter snow; Hallasan summit averages 4°C.

Temperature records range from −32.6°C (Yangpyeong, 1981) to 41.0°C (Hongcheon, 2018). Major events include Typhoon Maemi in September 2003 (130 deaths), the August 2020 monsoon with 54 rain days, the August 2022 Seoul Gangnam flooding exceeding 100 mm/hour, and the August 2018 heatwave reaching 41°C. Sea level is rising and threatening coastal regions.

Our archive covers 3 Korean cities with daily ERA5 reanalysis data going back to 1940. The warmest July averages occur in Seoul, around 28.3°C, while Seoul records the coldest January nights near −8.4°C. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 1.5°C.0°C at Hongcheon, and recurrent severe spring yellow-dust storms.