Larimer County (Fort Collins)
September
Weather in Larimer County, Colorado for September 2026
Your guide to Larimer County weather in September - trends and predictions
So far, September 2026 in Larimer County is slightly warmer than the historical average by 1.2 °F.
The forecast for the next days in Larimer County predicts temperatures to be around 26 °F, close to the historical average.
In general, the average temperature in Larimer County at the beginning of September is 28.7 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 25.3 °F by the end of September.
Larimer County experiences moderate rainfall in September, with an average of 7 rainy days and a total precipitation of 45.4 mm.
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Temperatures
Rain 🌧️
More
23
Dry days
7
Rainy days
0
Snow days
25°/12°
Temperatures
19 km/h
Avg max wind
41 %
Avg humidity
Larimer County Weather September
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Temperatures trend during September in Larimer County
See the weather trend as well as the moving average line
September weather in Larimer County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 30° /14° | 0 mm | 7 | |
| Sept. 2 | Sunny | 30° /14° | 0.3 mm | 7 | |
| Sept. 3 |  Patchy light drizzle | 31° /15° | 1.4 mm | 7 | |
| Sept. 4 | Sunny | 29° /13° | 1.4 mm | 8 | |
| Sept. 5 |  Partly cloudy | 25° /12° | 0.1 mm | 7 | |
| Sept. 6 | Sunny | 27° /11° | 0.9 mm | 7 | |
| Sept. 7 | Sunny | 29° /14° | 0.3 mm | 6 | |
| Sept. 8 | Sunny | 29° /14° | 0.3 mm | 7 | |
| Sept. 9 |  Overcast | 28° /13° | 0.6 mm | 7 | |
| Sept. 10 | Partly cloudy | 27° /12° | 1.5 mm | 7 | |
| Sept. 11 |  Fog | 26° /13° | 0.9 mm | 5 | |
| Sept. 12 | Sunny | 26° /11° | 0 mm | 6 | |
| Sept. 13 |  Cloudy | 27° /12° | 0.1 mm | 7 | |
| Sept. 14 | Overcast | 26° /13° | 0 mm | 5 | |
| Sept. 15 | Partly cloudy | 25° /11° | 0 mm | 7 | |
| Sept. 16 | Sunny | 26° /11° | 0.3 mm | 5 | |
| Sept. 17 | Partly cloudy | 24° /12° | 0 mm | 4 | |
| Sept. 18 | Overcast | 25° /11° | 0.5 mm | 4 | |
| Sept. 19 |  Thundery outbreaks possible | 25° /11° | 1.6 mm | 5 | |
| Sept. 20 | Patchy light drizzle | 25° /10° | 1 mm | 6 | |
| Sept. 21 | Overcast | 23° /10° | 3.4 mm | 5 | |
| Sept. 22 | Partly cloudy | 21° /9° | 20.5 mm | 5 | |
| Sept. 23 | Overcast | 22° /9° | 3.7 mm | 4 | |
| Sept. 24 | Partly cloudy | 22° /9° | 0 mm | 5 | |
| Sept. 25 | Sunny | 25° /10° | 0.1 mm | 6 | |
| Sept. 26 | Sunny | 29° /15° | 0 mm | 6.3 | |
| Sept. 27 | Overcast | 29° /16° | 0.2 mm | 6.3 | |
| Sept. 28 | Overcast | 24° /17° | 0.1 mm | 4.1 | |
| Sept. 29 | Overcast | 23° /17° | 0.1 mm | 4.7 | |
| Sept. 30 | Overcast | 25° /15° | 0 mm | 6.3 | |
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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.
Change Month
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 25° and cooler nights around 12°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Larimer County during September?
In September, Larimer County can expect light to moderate rainfall, totaling 45.4 mm across approximately 7 days. Occasional showers are possible, and planning ahead for them could be helpful.
What are the typical wind conditions in Larimer County during September?
The average wind speed in Larimer County during September is 19 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 💧
Typically, Larimer County has 7 rainy days in September with a total of 45.4 mm of rainfall.
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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