South Korea most of which is not arable. Lowlands, located primarily in the west and southeast, make up only 30% of the total land area. About three thousand islands, mostly small and uninhabited, lie off the western and southern coasts of South Korea. Jeju-do is about off the southern coast of South Korea. It is the country's largest island, with an area of . Jeju is also the site of South Korea's highest point: Hallasan, an extinct volcano, reaches above sea level. The easternmost islands of South Korea include Ulleungdo and Liancourt Rocks (Dokdo/Takeshima), while Marado and Socotra Rock are the southernmost
Hallasan from the sea is formed on the coastal area and the peak temperature is mainly observed during the daytime. The change of the minimum temperature varies depending on the degree of cooling of Hallasan and the intensity of the wind speed.When the wind blows due to the predominance of sea breeze, the air cooled in Hallasan descends to the coastal area and induces the decrease in temperature. When the synoptic wind blows strongly, the cold air of Hallasan moves to the downwind side and the lowest temperature appears. The lowest temperature in the downwind area is 2 ~ 5℃ lower