Larimer County (Fort Collins)
September
Weather in Larimer County for September 2025
Your guide to Larimer County weather in September - trends and predictions
In general, the average temperature in Larimer County 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.
Larimer County 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
Larimer County 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 Larimer County
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 Larimer County 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 Larimer County forecast closer to your planned date for the most up-to-date weather information.
Larimer County in September - FAQ
What are the expected maximum and minimum temperatures in Larimer County 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 Larimer County during September?
Expect minimal rainfall in Larimer County 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 Larimer County during September?
The average wind speed in Larimer County during September is 18 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Larimer County
Explore the daily rainfall trends and prepare for Larimer Countys September weather 💧
UV exposure in Larimer County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is Larimer County?Get accurate weather forecasts for Larimer County, located at latitude 40.585 and longitude -105.084. Stay updated with localized weather information tailored for Larimer County.
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