S
M
T
W
T
F
S
30
77°
40°
31
76°
39°
1
72°
42°
2
71°
39°
3
69°
40°
4
70°
37°
5
68°
37°
6
70°
38°
7
73°
34°
8
72°
39°
9
72°
40°
10
69°
34°
11
67°
33°
12
68°
38°
13
69°
32°
14
68°
35°
15
72°
36°
16
74°
39°
17
75°
36°
18
74°
28°
19
65°
30°
20
70°
34°
21
72°
36°
22
74°
29°
23
72°
26°
24
64°
25°
25
68°
27°
26
62°
26°
27
68°
33°
28
67°
24°
29
62°
25°
30
Hist. Avg.
66°
28°
1
Hist. Avg.
66°
27°
2
Hist. Avg.
65°
27°
3
Hist. Avg.
65°
26°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Gunnison
Gunnison's September 2026 forecast shows daily high temperatures ranging from 62° to 77°, with overnight lows between 24° and 42°. The average high for September is 70° with an average low of 34°. 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 Gunnison. See also: October | November | December.