Jeju Island in September
In September, Jeju Island averages 25°C (77°F) during the day and 22°C (71°F) at night, with frequent rain — about 17 days of the month see precipitation (359 mm total).
ShoulderConditions are comfortable for sightseeing without being sweltering. Expect daily rain or showers, often in heavy bursts.
September offers comfortable temperatures in Jeju Island, with some rain to plan around.
How September compares to the rest of the year in Jeju Island
September is one of the warmest months in Jeju Island (3rd of 12) and one of the wettest months (3rd of 12). Daytime temperature runs 7°C above the annual average (18°C). September runs 4°C cooler than August (29°C) and cools 5°C in October (20°C).
September sunrise & sunset in Jeju Island
Times shown for Jeju Island local time (Asia/Seoul), calculated for the 15th of September. They shift by a few minutes day to day across the month.
Photography light in Jeju Island — September
Golden-hour and blue-hour windows for the 15th of September, in Jeju Island's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — Jeju Island in September
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on September's tier (Shoulder) and Jeju Island's popularity.
September in South Korea — events that affect travel
Known cultural, religious, or national events that surge prices, fill hotels, or close businesses during this month. Plan around them, or build your itinerary around the ones you'd like to see.
Korea's major harvest festival — most Koreans travel home; Seoul empties out somewhat but transit out of the city books solid.
Plan: Good time to enjoy a quieter Seoul; bad time to try to take a KTX train south on the holiday's eve.
Crowds & pricing — September in Jeju Island
Jeju Island is in a shoulder season month — fewer crowds, slightly lower prices, and a calmer atmosphere than peak weeks. Most major sights stay open with normal hours, though a handful of seasonal restaurants or boat trips may run reduced schedules. Many regulars consider these months the best time to visit because you trade a small amount of weather reliability for a much more pleasant on-the-ground experience.
Why this tier: comfortable tourism weather
Sun & mosquito risk — September in Jeju Island
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Jeju Island in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 8°C / 46°F | 3°C / 38°F | 90 mm | 11 | — |
| February | 8°C / 47°F | 4°C / 38°F | 73 mm | 10 | — |
| March | 13°C / 55°F | 7°C / 45°F | 112 mm | 10 | — |
| April | 17°C / 62°F | 11°C / 52°F | 130 mm | 10 | — |
| May | 21°C / 71°F | 16°C / 60°F | 147 mm | 10 | — |
| June | 24°C / 76°F | 20°C / 67°F | 206 mm | 14 | — |
| July | 28°C / 83°F | 24°C / 75°F | 253 mm | 18 | — |
| August | 29°C / 84°F | 25°C / 77°F | 269 mm | 18 | — |
| September | 25°C / 77°F | 22°C / 71°F | 359 mm | 17 | — |
| October | 20°C / 69°F | 16°C / 61°F | 152 mm | 10 | — |
| November | 15°C / 60°F | 11°C / 51°F | 88 mm | 11 | — |
| December | 10°C / 49°F | 5°C / 42°F | 85 mm | 14 | — |
Other cities with similar September weather
🌍 See the full ranked list of climate twins for Jeju Island in September →
Frequently asked questions
How hot is Jeju Island in September?
In September, Jeju Island averages a high of 25°C (77°F) and a low of 22°C (71°F) — generally warm.
Does it rain a lot in Jeju Island in September?
September is quite rainy in Jeju Island, with about 17 rainy days on average.
Is September a good time to visit Jeju Island?
September is warm but on the rainy side. It suits travelers who are comfortable with warm weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for Jeju Island in September?
Pack light layers for warm days and cooler evenings, plus a compact umbrella or rain jacket. See the full September packing list for Jeju Island for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.