Rainy Season in Jeju — When It Is & What to Expect
Jeju has a distinct rainy season covering January, March to September and November, when roughly 1842mm of rain falls — the bulk of the annual total. The wettest month is September (482.5mm over about 18 rainy days). Outside these months rainfall drops sharply, which is why the best time to visit is All year.
Jeju — Monthly Rainfall
Average monthly rainfall in millimetres, calculated from 2020–2023 data. Highlighted bars mark the rainy season.
Rainfall in Jeju month by month
| Month | Rain | Rainy days | High | Rating |
|---|---|---|---|---|
| January Wet | 119.8mm | 14 | 8.3°C | 9/10 |
| February | 82.5mm | 13 | 9.5°C | 10/10 |
| March Wet | 129.4mm | 11 | 14.4°C | 9/10 |
| April Wet | 115.7mm | 8 | 16.9°C | 9/10 |
| May Wet | 161.4mm | 11 | 21.9°C | 9/10 |
| June Wet | 199.9mm | 13 | 25.7°C | 9/10 |
| July Wet | 271.7mm | 19 | 28.8°C | 8/10 |
| August Wet | 259.4mm | 19 | 30.0°C | 8/10 |
| September Wet | 482.5mm | 18 | 25.7°C | 8/10 |
| October | 54.2mm | 8 | 20.4°C | 10/10 |
| November Wet | 102.3mm | 12 | 16.1°C | 9/10 |
| December | 93.7mm | 15 | 9.7°C | 10/10 |
Should you visit Jeju during rainy season?
It can still work. Rain in the wet season often falls in short, intense bursts rather than all-day washouts, prices are lower and crowds thinner. But expect high humidity, disrupted boat trips and island transfers, and the occasional flooded street — September in particular is best avoided.
Best time to avoid the rain
The driest, most comfortable window is All year — see the full best time to visit Jeju guide for the month-by-month breakdown.
Frequently Asked Questions
When is rainy season in Jeju?
Rainy season in Jeju runs January, March to September and November, peaking in September with 482.5mm of rain.
What is the wettest month in Jeju?
September — averaging 482.5mm of rain over roughly 18 rainy days.
Can you visit Jeju during rainy season?
It can still work. Rain in the wet season often falls in short, intense bursts rather than all-day washouts, prices are lower and crowds thinner. But expect high humidity, disrupted boat trips and island transfers, and the occasional flooded street — September in particular is best avoided.
When is the dry season in Jeju?
The driest, most comfortable months are All year — see the best time to visit Jeju guide.
Travelling in the wet season anyway?
Pack right for it — the full checklist is on our sister site.
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Check your Jeju packing list at 247PackingList for a full wet-season checklist. For country facts, see our South Korea guide at 247CountryInfo.
Wet season essentials for Jeju
Compact travel umbrella
Windproof, fits in a daypack, dries fast — non-negotiable in monsoon season.
Check Price →Packable waterproof jacket
Light enough for the humidity, sealed enough for the downpours.
Check Price →Dry bag
Keeps phones, passports and cameras dry through boat trips and sudden storms.
Check Price →More wet-season travel gear
Quick-dry travel clothing
Lightweight and quick-drying — ideal for high-humidity wet seasons.
Check Price →Last updated:
Climate data sourced from Open-Meteo (open source, open data licence). Monthly averages calculated from 2020–2023 historical data. Weather can be unpredictable — always check a live forecast before travelling.