S
M
T
W
T
F
S
30
79°
47°
31
77°
45°
1
78°
47°
2
78°
45°
3
81°
50°
4
82°
50°
5
85°
49°
6
Hist. Avg.
80°
46°
7
Hist. Avg.
80°
45°
8
Hist. Avg.
80°
45°
9
Hist. Avg.
79°
45°
10
Hist. Avg.
79°
44°
11
Hist. Avg.
78°
44°
12
Hist. Avg.
78°
44°
13
Hist. Avg.
77°
43°
14
Hist. Avg.
77°
43°
15
Hist. Avg.
76°
43°
16
Hist. Avg.
76°
42°
17
Hist. Avg.
75°
42°
18
Hist. Avg.
75°
42°
19
Hist. Avg.
74°
41°
20
Hist. Avg.
74°
41°
21
Hist. Avg.
73°
40°
22
Hist. Avg.
72°
40°
23
Hist. Avg.
72°
40°
24
Hist. Avg.
71°
39°
25
Hist. Avg.
71°
39°
26
Hist. Avg.
70°
38°
27
Hist. Avg.
70°
38°
28
Hist. Avg.
69°
38°
29
Hist. Avg.
68°
37°
30
Hist. Avg.
68°
37°
1
Hist. Avg.
67°
36°
2
Hist. Avg.
67°
36°
3
Hist. Avg.
66°
36°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Casper
Casper's September 2026 forecast shows daily high temperatures ranging from 77° to 85°, with overnight lows between 45° and 50°. The average high for September is 80° with an average low of 48°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Casper. See also: October | November | December.
