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United States weather

Weather in Casper, Wyoming for September 2025

Your guide to Casper weather in September - trends and predictions

    Temperatures

  • Until now, September 2025 in Casper has been nearly identical to the historical average, with a temperature of 26.5 °F (showing only a slight deviation of 0.1 °F).

  • Expect cooler weather in the next days in Casper with the forecast suggesting a temperature of 24.9 °F, lower than the historical average.

  • In general, the average temperature in Casper at the beginning of September is 25.1 °F. As the month progressed, temperatures tended to moderately rise, reaching an average of 26.1 °F by the end of September.

    • Rain 🌧️

  • With an average of 2 rainy days, Casper experiences minimal rainfall in September.

    • More

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Average dry days
28
Dry days
Average rainy days
2
Rainy days
Average snowy days
0
Snow days
Average temperatures
25°/10°
Temperatures
Average wind speed
25 km/h
Avg max wind
Average humidity
37 %
Avg humidity

Casper Weather September

Move between months or click on a day
August
October
Sun.Mon.Tue.Wed.Thu.Fri.Sat.
1
Sunny
27°
2
Sunny
28°
3
Sunny
26°
4
Sunny
27°
5
Overcast
19°
6
Sunny
22°
7
Thundery outbreaks possible
27°
8
Partly cloudy
27°
9
Cloudy
29°
10
Sunny
30°
11
Patchy rain possible
29°
12
Sunny
26°
13
Sunny
22°
14
Partly cloudy
26°
15
Sunny
28°
16
Sunny
22°
17
Sunny
23°
18
Sunny
25°
19
Sunny
24°
20
Sunny
23°
21
Patchy rain possible
26°
22
Patchy rain possible
21°
23
Sunny
24°
24
Sunny
27°
25
Sunny
24°
26
Sunny
28°
27
Sunny
27°
28
Partly cloudy
30°
29
Sunny
31°
30
Sunny
16°

Temperatures trend during September in Casper

See the weather trend as well as the moving average line

September weather in Casper day by day

Click on a date for more information
August October
Date Weather Temperatures Rain UV More
Sept. 1 Sunny
Sunny
 27° /10° 0 mm 7
Sept. 2 Sunny
Sunny
 28° /10° 0 mm 7
Sept. 3 Sunny
Sunny
 26° /11° 0 mm 7
Sept. 4 Sunny
Sunny
 27° /11° 0 mm 7
Sept. 5 Overcast
Overcast
 19° /8° 0 mm 4
Sept. 6 Sunny
Sunny
 22° /4° 0 mm 6
Sept. 7 Thundery outbreaks possible
Thundery outbreaks possible
 27° /8° 0 mm 6
Sept. 8 Partly cloudy
Partly cloudy
 27° /11° 0 mm 7
Sept. 9 Cloudy
Cloudy
 29° /11° 0 mm 7
Sept. 10 Sunny
Sunny
 30° /12° 0 mm 8
Sept. 11 Patchy rain possible
Patchy rain possible
 29° /12° 0.1 mm 7
Sept. 12 Sunny
Sunny
 26° /11° 0 mm 7
Sept. 13 Sunny
Sunny
 22° /8° 0 mm 6
Sept. 14 Partly cloudy
Partly cloudy
 26° /10° 0 mm 1.5
Sept. 15 Sunny
Sunny
 28° /10° 0 mm 1.5
Sept. 16 Sunny
Sunny
 22° /10° 0 mm 1.2
Sept. 17 Sunny
Sunny
 23° /9° 0.1 mm 1.4
Sept. 18 Sunny
Sunny
 25° /11° 0 mm 0
Sept. 19 Sunny
Sunny
 24° /9° 0 mm 5
Sept. 20 Sunny
Sunny
 23° /13° 0 mm 5
Sept. 21 Patchy rain possible
Patchy rain possible
 26° /12° 1.7 mm 4
Sept. 22 Patchy rain possible
Patchy rain possible
 21° /14° 0.3 mm 4
Sept. 23 Sunny
Sunny
 24° /11° 0 mm 5
Sept. 24 Sunny
Sunny
 27° /11° 0 mm 5
Sept. 25 Sunny
Sunny
 24° /11° 0 mm 5
Sept. 26 Sunny
Sunny
 28° /10° 0 mm 5
Sept. 27 Sunny
Sunny
 27° /11° 0 mm 5
Sept. 28 Partly cloudy
Partly cloudy
 30° /10° 0 mm 8
Sept. 29 Sunny
Sunny
 31° /12° 0 mm 8
Sept. 30 Sunny
Sunny
 16° /2° 0 mm 5
Next
Important Notice
Our weather forecast for Casper 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 Casper forecast closer to your planned date for the most up-to-date weather information.
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Casper in September - FAQ

What are the expected maximum and minimum temperatures in Casper during September?
Enjoy moderate daytime temperatures of up to 25° and cooler nights around 10°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Casper during September?
Expect minimal rainfall in Casper during September, with a total of 11.2 mm over approximately 2 days. This minimal precipitation is unlikely to significantly impact plans.
What are the typical wind conditions in Casper during September?
The average wind speed in Casper during September is 25 km/h, suggesting breezy to windy conditions, depending on your activities.

September rainfall patterns in Casper

Explore the daily rainfall trends and prepare for Caspers September weather 💧

UV exposure in Casper during September

Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️

Quick links

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Location coordinates 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.

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