Due to the influence of the East Asian monsoon, Korea experiences high temperatures and humidity during the summer, while the winter climate is characterized by being very dry and cold. The climatic distribution of Korea is formed through the complex interaction of various climate factors, including geographical location, altitude above sea level, topographical characteristics, land-sea distribution, ocean currents, the East Asian monsoon, and weather fronts (the boundaries between different air masses).

Because of the Korean Peninsula’s long north–south extent, temperatures differ markedly by latitude, reflecting variations in solar radiation and sunshine duration. The mean annual temperature at the southernmost point, Seogwipo (33° 14’ N), is 16.9°C, whereas Cheorwon (38° 08’ N), located in the central part of the Peninsula, is 10.3°C, showing a significant temperature difference by latitude. Altitude also acts as a crucial climate factor. Daegwallyeong (773 m above sea level), the highest-elevation observation point, has a mean annual temperature of 7.1°C, which is approximately 3.7°C lower than Hongcheon (141 m above sea level) by 10.8°C, even though the two locations lie at similar latitudes. This altitudinal effect is also evident in southern regions: Imsil (248 m above sea level) averages 11.3°C compared with a 13.3°C average in lower-lying Jeongeup (45 m above sea level).

The Taebaeksanmaek (Taebaek Mountain Range) forms a powerful topographic barrier, creating a climatic contrast between the windward and leeward slopes. When the northwestern winter monsoon dominates, the Yeongseo region (Chuncheon), on the windward slope, experiences much colder temperatures, while the Yeongdong region (Sokcho), on the leeward slope, remains relatively mild. In January, the average monthly minimum temperature in Chuncheon is -9.3°C, compared with -3.8°C in Sokcho—a difference of 5.5°C.

Seasonal contrasts also appear in the summer. In August, the average monthly maximum temperature is higher in Chuncheon (29.9°C) than in Sokcho (27.5°C). When northeasterly airflows develop, moist air passing over the East Sea is forced upward along the Taebaeksanmaek, often producing concentrated snowfall and rainfall in the Yeongdong region. While Korea strongly exhibits the characteristics of a continental climate with a large annual temperature range, coastal areas show a climate distinct from the inland due to the moderating effect of the ocean. For instance, the annual temperature range in Daejeon, located inland, is 1.1°C larger than that of Boryeong, which is situated on the coast. Furthermore, the average temperature during the summer (June to August) in Daejeon is approximately 0.8°C higher than in Boryeong.

Ocean currents around the Korean Peninsula also influence the country’s climate. The East Korea Warm Current in the East Sea branches off from the eastern part of the Korea Strait, supplying warm seawater along the east coast up to approximately 37°–38° N latitude. In winter, it flows north as far as the coast of Goseong, Gangwon State, affecting the temperatures of the surrounding areas.

The North Korea Cold Current, derived from the Liman Cold Current, flows southward along the coast of Hamgyong-do and influences areas as far south as southern Gangwon State during the winter. Meanwhile, the Yellow Sea Warm Current flows northward from the west of Jeju Island into the southern Yellow Sea, impacting the climate of the west coast. This current exhibits seasonal variations, with its northward flow strengthening in summer and weakening in winter.