Verdict: Good month
Jeju Weather in September
September hits the sweet spot in Jeju — highs around 26°C (79°F), ideal for a full day on foot. It's also the wet side of the calendar: rain falls on about 18 days, so build flexibility into plans. Overall, September is a solid month to visit Jeju.
Average high
26°C / 79°F
Average low
22°C / 72°F
Rain days
~18
Precipitation
425 mm
What to pack for Jeju in September
- Summer clothes, plus one light layer for air-con and evenings
- Rain gear is non-negotiable — expect rain on roughly 18 days
- Quick-dry shoes — downpours are short but heavy
- Comfortable walking shoes — every guide on this site assumes you'll use them
September against the rest of the year
Warmest in Jeju: Aug (30°C / 86°F) · Coolest: Jan (8°C / 46°F) · Wettest: Jul (~20 rain days)
8°
3°
Jan
10°
4°
Feb
14°
7°
Mar
17°
11°
Apr
22°
15°
May
25°
20°
Jun
29°
24°
Jul
30°
25°
Aug
26°
22°
Sep
21°
16°
Oct
16°
11°
Nov
9°
5°
Dec
Daily highs / lows in °C · bars show rain days per month · ERA5 climate normals (2020–2024)