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 than in other areas, and the lowest temperature often appears at night. When the weak northwestern synoptic winds are blown, the lowest temperature appears in the eastern part of Jeju Island. The chill of the top of Hallasan descends downhill along the mountain range and is collected in the eastern part of Jeju Island so the morning temperature drops a lot. For the last five years, the deviation of temperature (maximum temperature - minimum temperature) increased in spring between March and May. The reason for the large deviation in spring is because the phenomenon occurs frequently by Hallasan. Hallasan was