Jeju Weather in May
🇰🇷 South Korea
Asia › 🇰🇷 South Korea › Jeju
Updated: March 2026
Is May a Good Time to Visit Jeju?
May is a good time to visit Jeju (6/10). With 9 daily sunshine hours and only 10 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 3rd sunniest of the year in Jeju. Culture-focused travellers and those who prefer lighter crowds will find May a practical choice, with prices running lower than peak August without sacrificing all the good weather. June offers a similar profile at lower hotel rates if dates are flexible. The main practical note: Jeju's popular sites are busiest between 10am and 3pm regardless of season. Arriving at opening time or after 4pm makes a significant difference to the experience. Planning tips: accommodation is generally available without long lead times, and flight prices are typically lower than peak season. Flexible travellers will find the best deals by booking 2-4 weeks ahead. Mid-week arrivals consistently unlock lower hotel rates than weekend check-ins.
Jeju in May rewards travelers with average highs of 20°C and overnight lows around 15°C. Expect around 10 rainy days, so a compact umbrella is worth carrying. With 9 daily sunshine hours on average, conditions are comfortable for sightseeing at a relaxed pace.
20°C
Avg High
15°C
Avg Low
10 days
Rain Days
9h
Sunshine
70%
Humidity
Temperature in Jeju in May
The narrow 5°C gap between daytime and overnight temperatures, characteristic of coastal cities with maritime moderation, means a single mid-layer works across the whole day. Humidity averages 70%, which is comfortable for most visitors. On warmer days, lighter fabrics help with the mild stickiness in the afternoon. UV index averages 9 this month, classed as high to very high. SPF 30+ sunscreen, a brim hat, and sunglasses are not optional between 10am and 4pm. Wind averages 16 km/h, light enough to be refreshing on warm days but noticeable in open coastal areas or elevated viewpoints. In Fahrenheit: 68°F average high, 59°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Temperature in May
Monthly Precipitation (mm)
What to Wear in Jeju in May
Packing for Jeju in May means dressing for 20°C days and 15°C evenings. A light cotton tee with a casual overshirt works well at 20°C, the overshirt doubles as a layer for air-conditioned venues. Evening temperatures settle at 15°C, a modest 5°C drop that a light cardigan or denim jacket covers. Comfortable walking trainers are the versatile choice for both outdoor sightseeing and indoor venues. A compact foldable umbrella weighs almost nothing and earns its keep across 10 potential rainy days.
Local tip: Temple and religious site visits require covered shoulders and knees in most of Jeju's heritage areas. A lightweight scarf or sarong weighs almost nothing and solves the problem instantly.
Events in Jeju in May
May has no major festivals or public holidays in Jeju, which is one of its practical advantages for independent travellers. Attractions run at lower capacity than during peak event periods, queues are shorter, and accommodation is easier to find without needing to book many months in advance. Local restaurants, markets, and transport operate at a relaxed pace, making this an ideal time for visitors who prefer a more authentic, unhurried experience of everyday city life rather than large crowds drawn in by a single major headline event.
What to Pack for Jeju in May
Based on 20°C average highs and 10 rainy days
- Light jacket or cardigan for cooler evenings
- Mix of short and long-sleeve layers
- Comfortable walking shoes with good arch support
- Compact folding umbrella
- Waterproof outer layer or packable rain jacket
- Quick-dry clothing that recovers fast after a shower
- Universal travel adapter
- Small day pack for city exploration
- Reusable water bottle
Best Activities in Jeju in May
- Explore outdoor markets and street food stallsMid-morning (10am-12pm)At 20°C, the temperature is ideal for extended walking without overheating
- Guided walking tour of the historic centreMorning or late afternoonComfortable temperatures allow several hours on foot without fatigue
- Visit rooftop viewpoints and observation decksGolden hour (1 hour before sunset)Warm clear evenings provide exceptional visibility for panoramic photography
- Day trip to the surrounding countryside or coastFull day (depart by 8am)May is reliably dry enough for rural day trips without weather risk
- Afternoon in a world-class museum or galleryAfternoon (2-5pm)Pairs well with outdoor morning activities and provides a mid-day rest from sightseeing
- Coffee-house or traditional cafe culture experienceMid-morning or post-lunchA cultural ritual in this region that rewards slow appreciation regardless of weather
- Evening live music, theatre, or opera performanceEvening shows typically at 7-9pmConsistent evening temperatures make getting to and from evening venues comfortable
- Visit the main botanical garden or city park at seasonal peakYear-round; best light in morningMay brings distinct seasonal changes to public green spaces worth exploring
- Try the seasonal farmer's market for local produce and street foodSaturday morning markets typically 8am-1pmMay seasonal produce is at peak availability, offering dishes not found at other times of year
Why is Jeju mild in May?
Jeju's May heat is driven by the Asian summer monsoon system, as the low-pressure cell that forms over the heated landmass draws warm, humid air from the oceans. The result is temperatures averaging 20°C with high moisture in the air. Overnight temperatures remain elevated at 15°C, as clouds and humidity prevent the earth from radiating heat away after sunset. Climate data: Open-Meteo ERA5 (1991–2020).
Sunshine Hours
The average number of hours per day with direct sunlight. Calculated from satellite measurements. Days with more than 7 hours of sunshine are ideal for outdoor activities. Under 3 hours means overcast conditions dominate.
UV Index
A scale from 0-11+ measuring ultraviolet radiation intensity. UV 0-2: Minimal risk. UV 3-5: Moderate -- wear sunscreen. UV 6-7: High -- hat and SPF 30+ essential. UV 8-10: Very High -- limit midday exposure. UV 11+: Extreme -- seek shade between 10am-4pm.
Rain Days
A rain day is counted when precipitation exceeds 0.1mm. This threshold captures even light drizzle. Unlike total rainfall in mm, rain days tells you how often you might need an umbrella, which is useful for planning outdoor activities.
Humidity
Relative humidity as a percentage. Below 40%: Dry -- skin and throat may feel parched. 40-60%: Comfortable -- ideal for most people. 60-80%: Sticky -- light, breathable fabrics recommended. Above 80%: Muggy -- heat feels more intense; quick-dry clothing is essential.
Frequently Asked Questions: Jeju in May
May ranks 3rd sunniest of the year in Jeju, with an average 9 daily sunshine hours. The driest months are October, February, and November. August is the hottest month (28°C avg high); January is the coolest (7°C). From here, temperatures rise 3°C into June. Compared to last month (April: 16°C high, 9 rain days), May is warmer and wetter. May is among the top three sunniest months to visit Jeju.
Year-Round Climate
Plan Your Trip to Jeju
Nearby Destinations with Similar Weather
These cities are within 500 km and experience broadly comparable weather conditions during the same calendar month, making them practical standalone alternatives or worthwhile additions to a longer regional itinerary.
Data Sources for Jeju
Climate normals represent 30-year averages (1991-2020). Individual years may vary.