More than 3,000 islands dot the coastline. The largest, about 60 km off the southwestern tip of the peninsula, is semi-tropical Jeju Island, among Koreans a popular honeymoon destination. There are several major rivers in the south, the greatest of them being the Han, which cuts through Seoul as it winds its way toward the East Sea. Like other countries in the temperate zone, Korea has four distinct seasons. Summer is hot and humid, with heavy rainfall occurring during the monsoon season.
Winter is cold and dry, with occasional snow.
However, these cold spells alternate with periods of milder weather held to occur with more or less predictable frequency. While by no means unvarying, these patterns occur with such a surprising degree of regularity, that it is not unusual for a Korean calendar to pinpoint, as if they were holidays, the hottest and coldest days of the year.