April 18 is generally a great time to visit Jeju Island. While there is a slight chance of rain (20%), showers are usually brief. Expect comfortable 18°C weather. Jeju Island is seeing high visitor numbers, so iconic spots may be busier than usual.
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Essential Travel Info for Jeju Island
Currency
KRW
₩ South Korean won
Language
Korean
Driving
Right side
Safety
High Safety
GPI: 1.779
Jeju Island Weather Forecast for April 18
"Mild & Comfortable. Expect average highs of 17.6°C. 20% chance of rain."
What to Wear in Jeju Island in April
Based on historical data for April 18, Jeju Island typically experiences temperatures between 11.3°C and 17.6°C. We recommend packing light jacket, long pants to stay comfortable. Trends suggest it will stay mostly dry (20% rain probability), but checking the forecast before heading out is always wise.
Complete Packing Guide
Weekly breakdown & essential items for Jeju Island
Smart Suitcase
- Light Jacket
- Long Pants
Average High
17.6°C
Daytime Peak
Average Low
11.3°C
Nighttime Low
Feels Like
17.6°C
🌤️ Feels accurate
Rain Chance
20%
Avg 1.6mm if it rains
Cloud Cover
61%
Overcast
Pressure
1014.7 hPa
Medium volatility
Jeju Island Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 81% of the time. Safe to plan outdoor activities with confidence.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 30 recommended
06:00 - 10:00
16:00 - 19:00
Type I-II
🔴 19 min to burn
Type III-IV
🟡 29 min to burn
Type V-VI
🟢 48 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
13.1°C
Pleasant
Heat Stress
Low
No heat warning
😊 Best outdoor time:
Any time during daylight hours
Marine Conditions
Marine Life
No special warnings. Enjoy the swim!
Swim Index
❄️ Cold Water Hazard
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in South Korea
Flight Traffic
Busy
67/100 pressure index
Health Advisory
Required
2 vaccines • View Details →
Landing Slots
~165
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Jeju Island
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
06:01
☀️ Noon
12:34
🌇 Sunset
19:07
⏱️ Daylight
13h 5m
Wind Speed
14.9 km/h
Gentle breeze
Sunshine
9.0 hrs
Direct Sun (Cloud-free)
Humidity
75%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Jeju Island
Smart Flight Estimator
Airport-to-Airport Logistics
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Travel Health & Safety in Jeju Island
Travel Comfort Index
Real-time tourism conditions
Weather Quality
☀️ Excellent
Tourist Crowds
🟡 Busy
Price Level
💰💰 Moderate
Health & Wellbeing
Meteo-Health Forecast
Moderate fluctuations. Some sensitivity possible.
Weather unlikely to affect joint pain.
Moderate fish activity expected.
Air quality is excellent. Perfect for outdoor activities.
Regional Safety Profile
Seismic Activity
Rare minor tremors. Buildings are earthquake-resistant.
Typhoon Risk
Year-round risk present
Travel Alert: This region has elevated natural risks. We recommend registering with your embassy and keeping emergency numbers handy.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Jeju Island on April 18 averages 17.6°C with a 20% precipitation probability. Wedding/Outdoor Event Score: 93/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Jeju Island Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
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📍 Is Jeju Island Worth Visiting on April 18?
Planning a trip to Jeju Island on April 18? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year is characterized by pleasant mild weather averaging 17.6°C with a 20% historical precipitation risk.
✈️ Travel Logistics: Approximately 165 landing slots available daily during this period, indicating manageable crowd levels.
💉 Health Advisory: 10 vaccinations are recommended for South Korea, including COVID-19.
🌊 Coastal Conditions: Water temperature averages 15.5°C (polar plunge). Wave conditions are generally fun waves with heights around 0.71m.
📊 Historical Extremes: The hottest April 18 recorded in the last 30 years saw temperatures hit 25.8°C in 2025, while the coldest dropped to 7.4°C in 2018.