Jeju is pleasant year-round by Korean standards, but the island has a distinct character in each season. Spring (April to May) brings camellias, cherry blossoms, and yellow canola fields — the island's most photogenic time. Summer (June to August) is warm and humid, with typhoon risk in August; beaches are busy and accommodation expensive. Autumn (September to November) has clear skies and the best hiking conditions on Hallasan.
Winter is mild compared with the mainland — Jeju rarely sees snow below 200 metres, though Hallasan's summit gets significant snowfall. The haenyeo continue working year-round. Winter is the low season and room rates are low; January and February are the quietest months. The annual Jeju Cherry Blossom Festival in late March to early April is worth timing a visit around.
July and August are peak domestic tourism season; book accommodation well in advance for weekends.