Fort Collins
September
Weather in Fort Collins for September 2025
Your guide to Fort Collins weather in September - trends and predictions
In general, the average temperature in Fort Collins at the beginning of September is 29.3 °F. As the month progressed, temperatures tended to moderately fall, reaching an average of 27.3 °F by the end of September.
Fort Collins sees moderate rainfall in September, averaging 6 rainy days.
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24
Dry days
6
Rainy days
0
Snow days
26°/11°
Temperatures
18 km/h
Avg max wind
39 %
Avg humidity
Fort Collins in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  31° | 2  31° | 3  32° | 4  28° | 5 24° | 6  29° | 7 30° |
| 8 30° | 9  30° | 10  25° | 11  24° | 12 27° | 13 26° | 14 24° |
| 15 24° | 16 26° | 17 25° | 18 27° | 19 24° | 20 27° | 21 21° |
| 22 17° | 23 24° | 24 23° | 25 27° | 26 29° | 27 29° | 28 29° |
| 29 29° | 30 25° |
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Temperatures trend during September in Fort Collins
See the weather trend as well as the moving average line
September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 | Thundery outbreaks possible | 31° /14° | 0.1 mm | 8 | |
| Sept. 2 | Overcast | 31° /15° | 0.3 mm | 7 | |
| Sept. 3 | Patchy light drizzle | 32° /17° | 2.7 mm | 7 | |
| Sept. 4 | Partly cloudy | 28° /14° | 2.8 mm | 7 | |
| Sept. 5 | Partly cloudy | 24° /12° | 0.3 mm | 6 | |
| Sept. 6 | Sunny | 29° /11° | 0 mm | 7 | |
| Sept. 7 | Sunny | 30° /13° | 0.2 mm | 7 | |
| Sept. 8 | Sunny | 30° /14° | 0 mm | 8 | |
| Sept. 9 | Cloudy | 30° /14° | 1.2 mm | 7 | |
| Sept. 10 | Patchy rain possible | 25° /13° | 3 mm | 6 | |
| Sept. 11 | Fog | 24° /12° | 1.8 mm | 6 | |
| Sept. 12 | Sunny | 27° /10° | 0 mm | 7 | |
| Sept. 13 | Cloudy | 26° /11° | 0 mm | 7 | |
| Sept. 14 | Overcast | 24° /11° | 0 mm | 6 | |
| Sept. 15 | Partly cloudy | 24° /11° | 0 mm | 6 | |
| Sept. 16 | Sunny | 26° /10° | 0.6 mm | 6 | |
| Sept. 17 | Partly cloudy | 25° /11° | 0 mm | 6 | |
| Sept. 18 | Thundery outbreaks possible | 27° /9° | 0.1 mm | 6 | |
| Sept. 19 | Thundery outbreaks possible | 24° /11° | 0 mm | 6 | |
| Sept. 20 | Patchy light drizzle | 27° /10° | 0.2 mm | 7 | |
| Sept. 21 | Patchy rain possible | 21° /9° | 6.7 mm | 5 | |
| Sept. 22 | Partly cloudy | 17° /7° | 39.6 mm | 5 | |
| Sept. 23 | Sunny | 24° /7° | 0 mm | 6 | |
| Sept. 24 | Sunny | 23° /8° | 0 mm | 6 | |
| Sept. 25 | Sunny | 27° /10° | 0 mm | 7 | |
| Sept. 26 | Sunny | 29° /12° | 0 mm | 8 | |
| Sept. 27 | Sunny | 29° /15° | 0 mm | 7 | |
| Sept. 28 | Sunny | 29° /12° | 0 mm | 7 | |
| Sept. 29 | Sunny | 29° /11° | 0 mm | 8 | |
| Sept. 30 | Patchy light drizzle | 25° /10° | 0.4 mm | 6 | |
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Important Notice
Our weather forecast for Fort Collins 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 Fort Collins forecast closer to your planned date for the most up-to-date weather information.
Fort Collins in September - FAQ
What are the expected maximum and minimum temperatures in Fort Collins during September?
Enjoy moderate daytime temperatures of up to 26° and cooler nights around 11°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Fort Collins during September?
Expect minimal rainfall in Fort Collins during September, with a total of 15 mm over approximately 6 days. This minimal precipitation is unlikely to significantly impact plans.
What are the typical wind conditions in Fort Collins during September?
The average wind speed in Fort Collins during September is 18 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Fort Collins
Explore the daily rainfall trends and prepare for Fort Collinss September weather 💧
UV exposure in Fort Collins during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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