Weather in Casper, Wyoming for September 2026
Until now, September 2026 in Casper has been nearly identical to the historical average, with a temperature of 24.7 °F (showing only a slight deviation of 0.4 °F).
The forecast for the upcoming days in Casper predicts a temperature of 21.9 °F, which is slightly above the historical average.
In general, the average temperature in Casper at the beginning of September is 26.1 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 21.3 °F by the end of September.
With an average of 2 rainy days, Casper experiences minimal rainfall in September.
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Casper Weather September
Temperatures trend during September in Casper
September weather in Casper day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Sunny | 26° /11° | 0.4 mm | 7 | |
| Sept. 2 | Sunny | 27° /12° | 0 mm | 8 | |
| Sept. 3 | Sunny | 26° /12° | 0 mm | 8 | |
| Sept. 4 | Sunny | 28° /13° | 0 mm | 8 | |
| Sept. 5 |  Overcast | 24° /12° | 0 mm | 6 | |
| Sept. 6 | Sunny | 26° /10° | 0 mm | 7 | |
| Sept. 7 |  Thundery outbreaks possible | 26° /11° | 0 mm | 5 | |
| Sept. 8 |  Partly cloudy | 26° /11° | 0 mm | 8 | |
| Sept. 9 |  Cloudy | 28° /10° | 0 mm | 7 | |
| Sept. 10 | Sunny | 30° /11° | 0 mm | 8 | |
| Sept. 11 |  Patchy rain possible | 29° /12° | 0.1 mm | 6 | |
| Sept. 12 | Overcast | 26° /9° | 0 mm | 5 | |
| Sept. 13 | Overcast | 25° /10° | 0.5 mm | 5 | |
| Sept. 14 | Overcast | 25° /9° | 0.2 mm | 6 | |
| Sept. 15 | Partly cloudy | 25° /8° | 0 mm | 6 | |
| Sept. 16 |  Heavy rain at times | 24° /10° | 0.6 mm | 4 | |
| Sept. 17 |  Moderate or heavy rain shower | 18° /11° | 18 mm | 3 | |
| Sept. 18 | Sunny | 22° /10° | 5 mm | 6 | |
| Sept. 19 | Sunny | 23° /8° | 1.6 mm | 5 | |
| Sept. 20 | Sunny | 22° /8° | 1.5 mm | 5 | |
| Sept. 21 | Overcast | 20° /8° | 0 mm | 5 | |
| Sept. 22 | Sunny | 22° /6° | 0.4 mm | 5 | |
| Sept. 23 | Overcast | 21° /13° | 0 mm | 5.6 | |
| Sept. 24 | Overcast | 21° /12° | 0 mm | 6.2 | |
| Sept. 25 | Sunny | 24° /12° | 0 mm | 5.8 | |
| Sept. 26 | Sunny | 24° /13° | 0 mm | 5.8 | |
| Sept. 27 | Overcast | 25° /12° | 0.4 mm | 5 | |
| Sept. 28 | Sunny | 22° /6° | 3.7 mm | 6 | |
| Sept. 29 | Patchy rain possible | 14° /5° | 3.3 mm | 4 | |
| Sept. 30 | Sunny | 19° /7° | 0 mm | 5 | |
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Casper in September - FAQ
What are the expected maximum and minimum temperatures in Casper during September?
How much rainfall should be expected in Casper during September?
What are the typical wind conditions in Casper during September?
September rainfall patterns in Casper
UV exposure in Casper during September
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Where is Casper?Get accurate weather forecasts for Casper, located at latitude 42.867 and longitude -106.313. Stay updated with localized weather information tailored for Casper.