December 21 is generally a great time to visit Helsinki. While there is a slight chance of rain (29%), showers are usually brief. Expect comfortable 0°C weather. As it's peak season for Helsinki, we recommend booking your stay well in advance to secure the best rates.
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Essential Travel Info for Helsinki
Currency
EUR
€ Euro
Language
Finnish
+1 more
Driving
Right side
Connect
Much of Helsinki is blanketed withWi-Fi ...
Safety
Very High Safety
GPI: 1.439
Helsinki Weather Forecast for December 21
"Cold & Crisp. Expect average highs of 0.3°C. 29% chance of snow."
What to Wear in Helsinki in December
Based on historical data for December 21, Helsinki typically experiences temperatures between -3.3°C and 0.3°C. We recommend packing heavy coat, scarf, gloves to stay comfortable. With a 29% chance of rain, keeping a raincoat or umbrella handy is a smart move.
Complete Packing Guide
Weekly breakdown & essential items for Helsinki
Smart Suitcase
- Heavy Coat
- Scarf
- Gloves
Average High
0.3°C
Daytime Peak
Average Low
-3.3°C
Nighttime Low
Feels Like
-5.3°C
🥶 Wind chill effect
Snow Chance
29%
Avg 1.3mm if it snows
Snowfall
0.8 cm
~29% chance
Pressure
1006.7 hPa
High volatility
Helsinki Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
✓ Weather is generally predictable, but pack for minor variations. A light backup layer is recommended.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 15 for extended outdoor time
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
-1.6°C
Dry air
Heat Stress
Low
No heat warning
😣 Best outdoor time:
Midday (11 AM - 3 PM) when warmest
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 Finland
Flight Traffic
High
94/100 pressure index
Health Advisory
Required
1 vaccine • View Details →
Landing Slots
~579
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Helsinki
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
09:25
☀️ Noon
12:19
🌇 Sunset
15:13
⏱️ Daylight
5h 48m
Wind Speed
23.3 km/h
Moderate wind
Sunshine
0.8 hrs
Direct Sun (Cloud-free)
Humidity
87%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Helsinki
Smart Flight Estimator
Airport-to-Airport Logistics
unlock smart flight estimates
Add your home location in settings to see airport details.
Travel Health & Safety in Helsinki
Travel Comfort Index
Real-time tourism conditions
Weather Quality
⛅ Good
Tourist Crowds
🟡 Busy
Price Level
💰💰💰 Expensive
Health & Wellbeing
Meteo-Health Forecast
Rapid pressure changes detected. High risk for meteosensitive people.
Low pressure & humidity may aggravate joints.
Fish are active due to pressure changes.
Air quality is excellent. Perfect for outdoor activities.
Regional Safety Profile
Seismic Activity
Zero seismic activity detected in 30 years.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Helsinki on December 21 averages 0.3°C with a 29% precipitation probability. Wedding/Outdoor Event Score: 9/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Helsinki Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Better Alternatives Nearby
Consider these dates within ±7 days
December 15
1.2°C • 25% rain
Score
16
December 16
1.2°C • 25% rain
Score
16
December 17
1.2°C • 24% rain
Score
15
💡 Moving your event by a few days could significantly improve weather conditions
Compare Other Cities
Same date (December 21) in other destinations
🌍 Explore the same date in different destinations around the world
📍 Is Helsinki Worth Visiting on December 21?
Planning a trip to Helsinki on December 21? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year offers a bracing seasonal atmosphere averaging 0.3°C with a 29% historical precipitation risk.
✈️ Travel Logistics: Approximately 579 landing slots available daily during this period, indicating peak tourist activity.
💉 Health Advisory: 8 vaccinations are recommended for Finland, including COVID-19.
🌊 Coastal Conditions: Water temperature averages 0.7°C (polar plunge). Wave conditions are generally fun waves with heights around 0.78m.
📊 Historical Extremes: The hottest December 21 recorded in the last 30 years saw temperatures hit 7.9°C in 2015, while the coldest dropped to -10.2°C in 2021.