South Korea Jeju Island Weather in September — Climate Guide
September in Jeju Island is high
September is high for Jeju Island.
Pleasant warm + typhoon season. Chuseok mid-September — businesses close 3-5 days. Avoid travel during.
Travel score
Jeju Island September Weather Stats
Avg High
26°C
Avg Low
19°C
Rainy Days
9
200mm total
Sunshine
7h
Daily avg
Humidity
75%
high
UV Index
7
High
Wind
8 km/h
Gusts 25
Sea Temp
25°C
swimming
Crowds
Busy
At attractions
September Sunrise & Sunset
Air Quality
PM2.5
12 μg/m³
PM10
22 μg/m³
Status
good
Feels-Like Temperature & Wind
Feels like
Daytime
28°C
Nighttime
19°C
Humidity and wind affect how the actual temperature feels.
Wind
8 km/h
Max gust 25 km/h
Activities Recommended for September
September Travel Pros & Cons
Pros
- 26°C ideal
- Sea still warm
- Reduced summer crowds
Cons
- Chuseok closures mid-September
- Typhoon risk
- Variable weather
September Events & Festivals
- Chuseok mid-September (Korean Thanksgiving, businesses close 3-5 days)
- Typhoon season
Jeju Island in September — Full Picture
Pleasant warm + typhoon season. Chuseok mid-September — businesses close 3-5 days. Avoid travel during.
What to Wear & What to Pack
Pleasant + typhoon risk. T-shirt + light layers.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
16.7°C
9.7°C
9/mo
Summer (Jun·Jul·Aug)
27°C
21.3°C
11.7/mo
Autumn (Sep·Oct·Nov)
Current21.7°C
14.3°C
7.7/mo
Winter (Dec·Jan·Feb)
9.3°C
3.3°C
7.7/mo
Jeju Island Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| 8° | 2° | 8d·60mm | 5h | 65% | 2 | Quiet | Low season | |
| 9° | 3° | 8d·65mm | 6h | 68% | 3 | Quiet | Low season | |
| 12° | 5° | 9d·90mm | 7h | 70% | 5 | Moderate | Shoulder | |
| April (Best) | 17° | 10° | 9d·100mm | 8h | 70% | 6 | Very busy | Peak |
| May (Best) | 21° | 14° | 9d·100mm | 9h | 75% | 7 | Very busy | Peak |
| 24° | 18° | 11d·200mm | 6h | 80% | 8 | Moderate | Shoulder | |
| 28° | 22° | 13d·280mm | 6h | 80% | 9 | Busy | Peak | |
| 29° | 24° | 11d·200mm | 7h | 78% | 10 | Very busy | Peak | |
| 26° | 19° | 9d·200mm | 7h | 75% | 7 | Busy | Peak | |
| October (Best) | 22° | 14° | 7d·100mm | 8h | 65% | 5 | Very busy | Peak |
| November (Best) | 17° | 10° | 7d·80mm | 7h | 60% | 3 | Busy | Peak |
| 11° | 5° | 7d·50mm | 6h | 60% | 2 | Moderate | Shoulder |
View Other Months
Jeju Island September Hotel Picks
Frequently Asked Questions
Is September a good time to visit Jeju Island?
Jeju Island in September is high. Tourist crowds are busy and flight/hotel prices are peak.
What's the average temperature in Jeju Island in September?
Jeju Island September averages a high of 26°C and a low of 19°C.
Does it rain much in Jeju Island in September?
Jeju Island September averages 200mm of rainfall over about 9 rainy days.
What should I wear in Jeju Island in September?
Pleasant + typhoon risk. T-shirt + light layers.
What time are sunrise and sunset in Jeju Island in September?
Jeju Island September sunrise is 06:35 and sunset is 18:35, with 12h of daylight.
What's the air quality like in Jeju Island in September?
Jeju Island September air quality (AQI) averages 35, rated Good. PM2.5 averages 12μg/m³.
What activities are recommended in Jeju Island in September?
In September, Jeju Island is great for Beach last warm, Hallasan early autumn foliage start, Seongsan + Manjanggul.
Is September peak season in Jeju Island?
Jeju Island September crowds are busy and prices are peak. Advance reservations are strongly recommended.
Best Months to Visit Jeju Island
View Other Months
Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.