🇰🇷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 3,000 to 3,600 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 cooler humid continental (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 has January highs of 2°C and lows of −6°C and August highs of 30°C with 1,420 mm rainfall concentrated June–September; Busan on the south coast records January highs of 8°C (lows 0°C) and August highs of 30°C with 1,580 mm; Jeju 9°C (4°C) and 30°C with 1,500 mm; Daegu in the southeast basin 6°C (−3°C) and 31°C with 1,080 mm; Gangneung on the east coast 5°C (−3°C) and 29°C with 1,450 mm.

Temperature records range from −32.6°C (Yangpyeong, 1981) to 42.5°C (Yangsan, 2026). Major events include Typhoon Maemi in September 2003 (117 deaths), the record-long monsoon season of summer 2020, the August 2022 Seoul Gangnam flooding exceeding 100 mm/hour, the August 2018 heatwave reaching 41°C, and the March 2025 wildfires in the southeast, which killed 32 people. Sea level is rising and threatening coastal regions.

Our archive covers 59 Korean cities with daily ERA5 reanalysis data going back to 1940. The hottest July afternoons are in Daegu, with average highs around 30.1°C, while Hwado has the coldest January nights, with average lows near −9.1°C. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 1.8°C.