Weather in Larimer County, Colorado for September 2025
Until now, September 2025 in Larimer County is slightly cooler than the historical average by -1.8 °F.
Expect cooler weather in the next days in Larimer County with the forecast suggesting a temperature of 25.7 °F, lower than the historical average.
In general, the average temperature in Larimer County at the beginning of September is 28.4 °F. As the month progressed, temperatures tended to noticeably cool down, reaching an average of 26.1 °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 60 mm.
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Larimer County Weather September
Temperatures trend during September in Larimer County
September weather in Larimer County day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 30° /14° | 0 mm | 7 | |
| Sept. 2 |  Overcast | 30° /14° | 0.2 mm | 7 | |
| Sept. 3 |  Patchy light drizzle | 31° /15° | 1.8 mm | 7 | |
| Sept. 4 |  Partly cloudy | 29° /13° | 1.9 mm | 7 | |
| Sept. 5 | Partly cloudy | 23° /11° | 0.2 mm | 6 | |
| Sept. 6 | Sunny | 27° /10° | 0 mm | 7 | |
| Sept. 7 | Sunny | 29° /13° | 0.1 mm | 7 | |
| Sept. 8 | Sunny | 30° /14° | 0 mm | 7 | |
| Sept. 9 |  Cloudy | 29° /14° | 0.8 mm | 6 | |
| Sept. 10 | Partly cloudy | 26° /12° | 2 mm | 6 | |
| Sept. 11 |  Fog | 25° /13° | 1.2 mm | 6 | |
| Sept. 12 | Sunny | 26° /11° | 0 mm | 6 | |
| Sept. 13 | Cloudy | 25° /11° | 0 mm | 6 | |
| Sept. 14 | Overcast | 24° /11° | 0 mm | 5 | |
| Sept. 15 | Partly cloudy | 25° /11° | 0 mm | 6 | |
| Sept. 16 |  Patchy rain possible | 24° /13° | 1.2 mm | 1.3 | |
| Sept. 17 | Partly cloudy | 22° /11° | 0 mm | 1.2 | |
| Sept. 18 | Partly cloudy | 21° /12° | 0 mm | 1.2 | |
| Sept. 19 | Sunny | 27° /8° | 0 mm | 1.7 | |
| Sept. 20 | Partly cloudy | 29° /14° | 0.1 mm | 0 | |
| Sept. 21 | Partly cloudy | 24° /17° | 0 mm | 5 | |
| Sept. 22 | Sunny | 28° /13° | 0 mm | 5 | |
| Sept. 23 | Sunny | 27° /11° | 0 mm | 5 | |
| Sept. 24 | Partly cloudy | 30° /12° | 0 mm | 6 | |
| Sept. 25 | Sunny | 28° /17° | 0 mm | 6 | |
| Sept. 26 | Sunny | 31° /14° | 0 mm | 6 | |
| Sept. 27 | Patchy rain possible | 27° /15° | 0.1 mm | 5 | |
| Sept. 28 | Sunny | 24° /9° | 0 mm | 5 | |
| Sept. 29 | Sunny | 18° /8° | 0 mm | 4 | |
| Sept. 30 | Patchy light drizzle | 25° /10° | 0.4 mm | 6 | |
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Larimer County in September - FAQ
September rainfall patterns in Larimer County
UV exposure in Larimer County during 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.