September 15 is generally a great time to visit Washington DC. While there is a slight chance of rain (20%), showers are usually brief. Expect comfortable 26°C weather. Washington DC is currently in its most popular travel window, meaning vibrant crowds and premium pricing.
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Essential Travel Info for Washington DC
Currency
USD
$ United States dollar
Language
English
Driving
Right side
Connect
The D.C. government operates a network o...
Safety
Moderate Safety
GPI: 2.44
Washington DC Weather Forecast for September 15
"Warm & Sunny. Expect average highs of 26.1°C. 20% chance of rain."
What to Wear in Washington DC in September
Based on historical data for September 15, Washington DC typically experiences temperatures between 16.8°C and 26.1°C. We recommend packing t-shirt, light clothing 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 Washington DC
Smart Suitcase
- T-Shirt
- Light Clothing
Average High
26.1°C
Daytime Peak
Average Low
16.8°C
Nighttime Low
Feels Like
27°C
☀️ Feels accurate
Rain Chance
20%
Avg 1.2mm if it rains
Cloud Cover
53%
Overcast
Pressure
1018.7 hPa
Medium volatility
Washington DC Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 91% 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
🔴 28 min to burn
Type III-IV
🟡 42 min to burn
Type V-VI
🟢 70 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
20.6°C
Humid/Sticky
Heat Stress
Low
No heat warning
🙂 Best outdoor time:
Morning hours (before 11 AM)
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in United States
Flight Traffic
High
95/100 pressure index
Health Advisory
Healthy
Routine only • View Details →
Landing Slots
~447
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Washington DC
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:50
☀️ Noon
12:04
🌇 Sunset
18:18
⏱️ Daylight
12h 28m
Wind Speed
12.9 km/h
Gentle breeze
Sunshine
9.0 hrs
Direct Sun (Cloud-free)
Humidity
72%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Washington DC
Smart Flight Estimator
Airport-to-Airport Logistics
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Travel Health & Safety in Washington DC
Travel Comfort Index
Real-time tourism conditions
Weather Quality
☀️ Excellent
Tourist Crowds
🟡 Busy
Price Level
💰💰💰 Expensive
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
Zero seismic activity detected in 30 years.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Washington DC on September 15 averages 26.1°C with a 20% precipitation probability. Wedding/Outdoor Event Score: 98/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Washington DC Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
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📍 Is Washington DC Worth Visiting on September 15?
Planning a trip to Washington DC on September 15? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year typically offers vibrant summer conditions averaging 26.1°C with a 20% historical precipitation risk.
✈️ Travel Logistics: Approximately 447 landing slots available daily during this period, indicating peak tourist activity.
📊 Historical Extremes: The hottest September 15 recorded in the last 30 years saw temperatures hit 32°C in 2021, while the coldest dropped to 11.1°C in 2020.