December 21 sees frequent showers in Portland. Historical data shows a 59% chance of rain, so pack accordingly. Temperatures average 8°C. Portland is seeing high visitor numbers, so iconic spots may be busier than usual.
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Essential Travel Info for Portland
Currency
USD
$ United States dollar
Language
English
Driving
Right side
Safety
Moderate Safety
GPI: 2.44
Portland Weather Forecast for December 21
"Rainy & Overcast. Expect average highs of 7.5°C. 59% chance of snow."
What to Wear in Portland in December
Based on historical data for December 21, Portland typically experiences temperatures between 1.7°C and 7.5°C. We recommend packing heavy coat, scarf, gloves along with other layers to stay comfortable. With a 59% chance of rain, keeping a raincoat or umbrella handy is a smart move.
Complete Packing Guide
Weekly breakdown & essential items for Portland
Smart Suitcase
- Heavy Coat
- Scarf
- Gloves
- Umbrella
Average High
7.5°C
Daytime Peak
Average Low
1.7°C
Nighttime Low
Feels Like
5°C
❄️ Slightly colder
Snow Chance
59%
Avg 5.6mm if it snows
Snowfall
0.4 cm
~59% chance
Pressure
1018.2 hPa
High volatility
Portland Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 86% of the time. Safe to plan outdoor activities with confidence.
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
5.5°C
Dry air
Heat Stress
Low
No heat warning
😕 Best outdoor time:
Midday (11 AM - 3 PM) when warmest
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in United States
Flight Traffic
Busy
78/100 pressure index
Health Advisory
Healthy
Routine only • View Details →
Landing Slots
~253
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Portland
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
07:49
☀️ Noon
12:10
🌇 Sunset
16:31
⏱️ Daylight
8h 41m
Wind Speed
14.1 km/h
Gentle breeze
Sunshine
3.2 hrs
Direct Sun (Cloud-free)
Humidity
87%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Portland
Smart Flight Estimator
Airport-to-Airport Logistics
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Travel Health & Safety in Portland
Travel Comfort Index
Real-time tourism conditions
Weather Quality
🌧️ Variable
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 acceptable. Sensitive individuals should limit prolonged outdoor exertion.
Regional Safety Profile
Seismic Activity
Rare minor tremors. Buildings are earthquake-resistant.
Volcanic Activity
Nearest: Mount St. Helens
84km away
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Portland on December 21 averages 7.5°C with a 59% precipitation probability. Wedding/Outdoor Event Score: 30/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Portland Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Better Alternatives Nearby
Consider these dates within ±7 days
December 14
7.8°C • 48% rain
Score
41
December 15
7.7°C • 45% rain
Score
41
December 16
7.7°C • 48% rain
Score
40
💡 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 Portland Worth Visiting on December 21?
Planning a trip to Portland 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 7.5°C with a 59% historical precipitation risk.
✈️ Travel Logistics: Approximately 253 landing slots available daily during this period, indicating manageable crowd levels.
📊 Historical Extremes: The hottest December 21 recorded in the last 30 years saw temperatures hit 14.1°C in 2020, while the coldest dropped to -7.1°C in 2022.