Jeju has aspects of both the continental and oceanic climates.
The temperature during the hottest summer months averages no higher than 34.7°C (93°F) and no less than -1.5°C (29°F) during the winter.
September through October is quite pleasant in Jeju. Temperatures can be around 16°C (60°F) – 27°C (80°F). Average humidity is around 65%-75%. Since October will be autumn season, come prepared for warm days and cool evenings and nights.
As mentioned on the Jeju Tour link, there are beautiful spots for hiking on this island. We are especially referring to a high mountain peak included in the tour planned for Jeju. There will be some “heavy duty” walking up the mountaintop, and we strongly recommend that you bring very comfortable shoes to climb the mountain and walk around other places of interest. Don’t forget:
- hat with brim or visor
- walking shoes
- long sleeve shirt and comfortable clothing
- wind proof jacket