Weather in Loudoun County, Virginia for September 2025
Until now, September 2025 in Loudoun County has been nearly identical to the historical average, with a temperature of 25.5 °F (showing only a slight deviation of -0.2 °F).
The forecast for the upcoming days in Loudoun County predicts a temperature of 27.6 °F, which is slightly above the historical average.
In general, the average temperature in Loudoun County at the beginning of September is 25.6 °F. As the month progressed, temperatures tended to moderately rise, reaching an average of 27.4 °F by the end of September.
The climate of Loudoun County in September is notably wet, with an average of 14 rainy days, and a total of 123.2 mm of precipitation.
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Loudoun County Weather September
Temperatures trend during September in Loudoun County
September weather in Loudoun County day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Moderate or heavy rain shower | 26° /16° | 3.3 mm | 6 | |
| Sept. 2 |  Partly cloudy | 24° /13° | 0 mm | 6 | |
| Sept. 3 |  Sunny | 24° /13° | 0 mm | 6 | |
| Sept. 4 |  Overcast | 27° /14° | 13.2 mm | 6 | |
| Sept. 5 | Partly cloudy | 28° /14° | 6.1 mm | 7 | |
| Sept. 6 | Overcast | 28° /16° | 8.8 mm | 7 | |
| Sept. 7 |  Heavy rain at times | 22° /14° | 1.8 mm | 5 | |
| Sept. 8 | Sunny | 22° /9° | 0 mm | 6 | |
| Sept. 9 | Sunny | 25° /9° | 0 mm | 7 | |
| Sept. 10 | Sunny | 26° /10° | 0 mm | 6 | |
| Sept. 11 | Sunny | 27° /14° | 0 mm | 7 | |
| Sept. 12 | Sunny | 27° /13° | 0 mm | 7 | |
| Sept. 13 |  Patchy rain possible | 27° /14° | 0.1 mm | 7 | |
| Sept. 14 | Overcast | 29° /16° | 0 mm | 6 | |
| Sept. 15 |  Cloudy | 30° /14° | 0 mm | 1.1 | |
| Sept. 16 | Patchy rain possible | 19° /15° | 3 mm | 0.9 | |
| Sept. 17 |  Moderate rain | 16° /14° | 13.8 mm | 0.2 | |
| Sept. 18 | Partly cloudy | 30° /15° | 0 mm | 1.5 | |
| Sept. 19 | Sunny | 33° /16° | 0 mm | 0 | |
| Sept. 20 | Sunny | 25° /14° | 0 mm | 5 | |
| Sept. 21 | Sunny | 25° /12° | 0 mm | 5 | |
| Sept. 22 | Sunny | 27° /12° | 0 mm | 5 | |
| Sept. 23 | Sunny | 31° /13° | 0 mm | 6 | |
| Sept. 24 | Sunny | 33° /18° | 0 mm | 6 | |
| Sept. 25 | Sunny | 30° /14° | 0 mm | 6 | |
| Sept. 26 | Sunny | 27° /14° | 0 mm | 5 | |
| Sept. 27 | Sunny | 29° /14° | 0 mm | 6 | |
| Sept. 28 | Sunny | 32° /16° | 0 mm | 6 | |
| Sept. 29 | Heavy rain at times | 22° /19° | 4.3 mm | 5 | |
| Sept. 30 | Overcast | 19° /16° | 0 mm | 4 | |
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Loudoun County in September - FAQ
September rainfall patterns in Loudoun County
UV exposure in Loudoun County during September
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Where is Loudoun County?Get accurate weather forecasts for Loudoun County, located at latitude 39.116 and longitude -77.564. Stay updated with localized weather information tailored for Loudoun County.