September 21 is statistically one of the best days of the year in Copenhagen. With minimal rain risk (13%) and pleasant highs of 17°C, it's ideal for outdoor adventures. You'll find plenty of company in Copenhagen this month as tourism activity remains quite robust.
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Essential Travel Info for Copenhagen
Currency
DKK
kr Danish krone
Language
Danish
Driving
Right side
Connect
Libraries offer free internet access for...
Safety
Very High Safety
GPI: 1.296
Copenhagen Weather Forecast for September 21
"Mild & Comfortable. Expect average highs of 16.5°C. 13% chance of rain."
What to Wear in Copenhagen in September
Based on historical data for September 21, Copenhagen typically experiences temperatures between 11.4°C and 16.5°C. We recommend packing light jacket, long pants to stay comfortable. Trends suggest it will stay mostly dry (13% rain probability), but checking the forecast before heading out is always wise.
Complete Packing Guide
Weekly breakdown & essential items for Copenhagen
Smart Suitcase
- Light Jacket
- Long Pants
Average High
16.5°C
Daytime Peak
Average Low
11.4°C
Nighttime Low
Feels Like
16.5°C
🌤️ Feels accurate
Rain Chance
13%
Avg 0.8mm if it rains
Cloud Cover
63%
Overcast
Pressure
1016.5 hPa
High volatility
Copenhagen Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 96% of the time. Safe to plan outdoor activities with confidence.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 15 for extended outdoor time
Type I-II
🔴 42 min to burn
Type III-IV
🟡 63 min to burn
Type V-VI
🟢 105 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
12.8°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 Denmark
Flight Traffic
Busy
63/100 pressure index
Health Advisory
Required
1 vaccine • View Details →
Landing Slots
~268
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Copenhagen
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:53
☀️ Noon
12:04
🌇 Sunset
18:14
⏱️ Daylight
12h 20m
Wind Speed
21 km/h
Moderate wind
Sunshine
7.9 hrs
Direct Sun (Cloud-free)
Humidity
79%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Copenhagen
Smart Flight Estimator
Airport-to-Airport Logistics
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Add your home location in settings to see airport details.
Travel Health & Safety in Copenhagen
Travel Comfort Index
Real-time tourism conditions
Weather Quality
☀️ Excellent
Tourist Crowds
🟡 Busy
Price Level
💰💰💰 Expensive
Health & Wellbeing
Meteo-Health Forecast
Rapid pressure changes detected. High risk for meteosensitive people.
Weather unlikely to affect joint pain.
Fish are active due to pressure changes.
Air quality is excellent. Perfect for outdoor activities.
Regional Safety Profile
Seismic Activity
Rare minor tremors. Buildings are earthquake-resistant.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Copenhagen on September 21 averages 16.5°C with a 13% precipitation probability. Wedding/Outdoor Event Score: 97/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Copenhagen Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Compare Other Cities
Same date (September 21) in other destinations
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Rome
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London
United Kingdom
Amsterdam
Netherlands
🌍 Explore the same date in different destinations around the world
📍 Is Copenhagen Worth Visiting on September 21?
Planning a trip to Copenhagen on September 21? 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 16.5°C with a 13% historical precipitation risk.
✈️ Travel Logistics: Approximately 268 landing slots available daily during this period, indicating manageable crowd levels.
💉 Health Advisory: 7 vaccinations are recommended for Denmark, including COVID-19.
🌊 Coastal Conditions: Water temperature averages 17.3°C (refreshing tonic). Wave conditions are generally lake-like with heights around 0.35m.
📊 Historical Extremes: The hottest September 21 recorded in the last 30 years saw temperatures hit 22.3°C in 2018, while the coldest dropped to 8.6°C in 2021.