Fairfax (VA)
September
Weather in Fairfax, Virginia for September 2026
Your guide to Fairfax weather in September - trends and predictions
So far, September 2026 in Fairfax shows a warmer trend than usual by 3.4 °F.
The forecast for the next days in Fairfax predicts temperatures to be around 21 °F, close to the historical average.
In general, the average temperature in Fairfax at the beginning of September is 28.7 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 20.4 °F by the end of September.
Fairfax in September brings notable rainfall, with an average of 16 rainy days and a total precipitation of 239 mm.
New! Chat with our AI weatherman - it’s amazing and free.
Temperatures
Rain 🌧️
More
14
Dry days
16
Rainy days
0
Snow days
25°/18°
Temperatures
13 km/h
Avg max wind
69 %
Avg humidity
Fairfax Weather September
Move between months or click on a day
Temperatures trend during September in Fairfax
See the weather trend as well as the moving average line
September weather in Fairfax day by day
Click on a date for more information
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Patchy light drizzle | 30° /19° | 0.5 mm | 7 | |
| Sept. 2 |  Partly cloudy | 28° /19° | 39.3 mm | 7 | |
| Sept. 3 |  Sunny | 29° /17° | 0 mm | 6 | |
| Sept. 4 |  Overcast | 31° /17° | 3.1 mm | 7 | |
| Sept. 5 | Partly cloudy | 29° /18° | 1.1 mm | 6 | |
| Sept. 6 |  Patchy rain possible | 29° /18° | 24.3 mm | 7 | |
| Sept. 7 | Patchy rain possible | 25° /15° | 2.3 mm | 6 | |
| Sept. 8 | Sunny | 26° /12° | 0 mm | 7 | |
| Sept. 9 | Sunny | 27° /14° | 0 mm | 6 | |
| Sept. 10 | Sunny | 28° /17° | 1.2 mm | 5 | |
| Sept. 11 | Sunny | 27° /17° | 37.2 mm | 5 | |
| Sept. 12 | Sunny | 28° /17° | 0.7 mm | 6 | |
| Sept. 13 | Partly cloudy | 29° /18° | 0.6 mm | 5 | |
| Sept. 14 |  Mist | 28° /19° | 0 mm | 6 | |
| Sept. 15 | Partly cloudy | 27° /17° | 0 mm | 7 | |
| Sept. 16 | Overcast | 25° /16° | 4 mm | 6 | |
| Sept. 17 |  Moderate or heavy rain shower | 23° /17° | 46.7 mm | 5 | |
| Sept. 18 | Light rain | 26° /19° | 1.4 mm | 5 | |
| Sept. 19 | Partly cloudy | 27° /18° | 0 mm | 6.7 | |
| Sept. 20 | Partly cloudy | 30° /19° | 4.3 mm | 6.4 | |
| Sept. 21 | Patchy rain possible | 22° /18° | 3.5 mm | 2.8 | |
| Sept. 22 | Light rain shower | 19° /15° | 8.7 mm | 0.5 | |
| Sept. 23 | Patchy rain possible | 14° /11° | 14.6 mm | 0.9 | |
| Sept. 24 | Overcast | 19° /11° | 1 mm | 5 | |
| Sept. 25 | Sunny | 21° /12° | 0 mm | 6 | |
| Sept. 26 | Sunny | 21° /12° | 0 mm | 6 | |
| Sept. 27 | Overcast | 21° /13° | 0 mm | 6 | |
| Sept. 28 | Overcast | 17° /13° | 0 mm | 5 | |
| Sept. 29 | Sunny | 22° /15° | 0 mm | 6 | |
| Sept. 30 | Overcast | 22° /14° | 0 mm | 5 | |
| Next | |||||
Important Notice
Our weather forecast for Fairfax in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Fairfax forecast closer to your planned date for the most up-to-date weather information.
Change Month
Fairfax in September - FAQ
What are the expected maximum and minimum temperatures in Fairfax during September?
During September, expect a variety of temperatures with highs around 25° and lows near 18°, suitable for diverse activities and preferences.
How much rainfall should be expected in Fairfax during September?
Significant rainfall exceeding 239 mm is expected in Fairfax during September, occurring over more than 16 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Fairfax during September?
The average wind speed in Fairfax during September is 13 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Fairfax
Explore the daily rainfall trends and prepare for Fairfaxs September weather 💧
Typically, Fairfax has 16 rainy days in September with a total of 239 mm of rainfall.
UV exposure in Fairfax during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
Quick links
More Fairfax weather pages
You are here
Where is Fairfax?Get accurate weather forecasts for Fairfax, located at latitude 38.846 and longitude -77.306. Stay updated with localized weather information tailored for Fairfax.
Found a mistake?
We appreciate your attention to details. Tell us here.