September 15 is generally a great time to visit Portland. While there is a slight chance of rain (17%), showers are usually brief. Expect comfortable 24°C weather. Expect a bustling atmosphere in Portland right now—this is when the city truly comes alive with visitors.
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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 September 15
"Mild & Comfortable. Expect average highs of 23.9°C. 17% chance of rain."
What to Wear in Portland in September
Based on historical data for September 15, Portland typically experiences temperatures between 12.5°C and 23.9°C. We recommend packing t-shirt, light clothing to stay comfortable. Trends suggest it will stay mostly dry (17% rain probability), but checking the forecast before heading out is always wise.
Complete Packing Guide
Weekly breakdown & essential items for Portland
Smart Suitcase
- T-Shirt
- Light Clothing
Average High
23.9°C
Daytime Peak
Average Low
12.5°C
Nighttime Low
Feels Like
24.4°C
☀️ Feels accurate
Rain Chance
17%
Avg 1.1mm if it rains
Cloud Cover
51%
Overcast
Pressure
1014.6 hPa
Low volatility
Portland 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
Type I-II
🔴 30 min to burn
Type III-IV
🟡 45 min to burn
Type V-VI
🟢 75 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
17.4°C
Noticeable
Heat Stress
Low
No heat warning
😊 Best outdoor time:
Any time during daylight hours
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in United States
Flight Traffic
High
94/100 pressure index
Health Advisory
Healthy
Routine only • View Details →
Landing Slots
~305
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Portland
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:50
☀️ Noon
12:07
🌇 Sunset
18:24
⏱️ Daylight
12h 33m
Wind Speed
10.9 km/h
Light breeze
Sunshine
9.7 hrs
Direct Sun (Cloud-free)
Humidity
67%
Slightly humid
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
☀️ Excellent
Tourist Crowds
🟡 Busy
Price Level
💰💰💰 Expensive
Health & Wellbeing
Meteo-Health Forecast
Stable conditions. Low risk of headaches.
Weather unlikely to affect joint pain.
Moderate fish activity expected.
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 September 15 averages 23.9°C with a 17% precipitation probability. Wedding/Outdoor Event Score: 99/100."
— 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
September 8
26.2°C • 9% rain
Score
100
September 9
26.2°C • 9% rain
Score
100
September 10
26°C • 10% rain
Score
100
💡 Moving your event by a few days could significantly improve weather conditions
Compare Other Cities
Same date (September 15) in other destinations
🌍 Explore the same date in different destinations around the world
📍 Is Portland Worth Visiting on September 15?
Planning a trip to Portland on September 15? 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 23.9°C with a 17% historical precipitation risk.
✈️ Travel Logistics: Approximately 305 landing slots available daily during this period, indicating manageable crowd levels.
📊 Historical Extremes: The hottest September 15 recorded in the last 30 years saw temperatures hit 33°C in 2023, while the coldest dropped to 8.9°C in 2018.