What to expect in Jeju Island in September
September is a mixed month in Jeju Island. You get 26° / 20°, but manageable crowds at the big attractions. Worth it for the right traveller.
Jeju Island weather in September
Typical conditions in Jeju Island during September, based on long-run climate normals rather than any single year. Treat it as a planning guide, not a forecast.
| Average high | 26°C 79°F |
|---|---|
| Average low | 20°C 68°F |
| Rainfall | Wet 65/100 |
| Total rainfall | 228 mm9.0 in |
| Rainy days | 11 |
| Sea temperature | 25°C 76°F |
| Daylight | 12 h 23 min |
| How it feels | Warm and comfortable |
Average highs sit around 26°C with lows near 20°C. Expect a fair amount of rain, so plan indoor backups.
Crowds & demand
Crowd levels are Moderate for Jeju Island — manageable crowds at the big attractions.
Prices & value
This month counts as shoulder season: prices close to the yearly average.
What to pack
Light layers for 26°C days and something with sleeves for evenings, which cool to around 20°C. Add a compact rain shell and shoes you do not mind soaking; this is one of the wetter months.
What it costs
Costs in September sit around the yearly average for Jeju Island — neither a bargain nor a squeeze. Booking a few weeks out is usually enough. Compared with the most expensive month of the year, you are looking at roughly 31% less.
Who this month suits
- Anyone travelling on a budget
- People who would rather have space than perfect conditions
- Visitors who want to catch a festival
Events & what’s on
Look out for Chuseok while you’re there.
- Chuseok — Korea's lunar harvest holiday empties the island as families gather for ancestral rites.
Jeju Island in September compared with nearby months
If your dates are flexible by a few weeks, this is what shifting them actually buys you.
| Month | Temp | Crowds | Price | Score |
|---|---|---|---|---|
| July | 28° / 23° | High | $$ | 45 |
| August | 30° / 24° | High | $$ | 41 |
| September · This month | 26° / 20° | Moderate | $$ | 62 |
| October | 21° / 14° | Moderate | $$ | 59 |
| November | 16° / 9° | Moderate | $$ | 63 |
These months score higher for Jeju Island on the same blend of weather, crowds and price. Same destination, better odds.
Or go somewhere else in September
If the destination is negotiable but the month is not, these places are at their best in September.
Figures are climate normals and modelled estimates — a planning guide, not a forecast. We separate fact, estimate and recommendation. Updated October 2026
