Jeju's winters are cool and unpredictable, with temperatures fluctuating between -4°C and 18°C. Spring arrives in March, bringing warmer temperatures ranging from 3°C to 21°C. Summer is hot and humid, with temperatures often reaching the mid-30s from June to August. Autumn is mild, with temperatures gradually dropping from September to November. Winter returns in December, with temperatures again experiencing a wide range, typically between -2°C and 19°C.