S
M
T
W
T
F
S
30
88°
59°
31
89°
60°
1
90°
57°
2
84°
56°
3
81°
56°
4
82°
57°
5
85°
59°
6
83°
57°
7
82°
53°
8
77°
55°
9
77°
54°
10
78°
57°
11
80°
54°
12
87°
54°
13
77°
61°
14
86°
65°
15
88°
57°
16
85°
53°
17
76°
52°
18
77°
51°
19
82°
51°
20
82°
54°
21
81°
60°
22
82°
58°
23
76°
56°
24
71°
55°
25
74°
57°
26
77°
56°
27
76°
56°
28
77°
57°
29
75°
57°
30
70°
51°
1
68°
46°
2
67°
45°
3
67°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Colorado
Colorado's September 2026 forecast shows daily high temperatures ranging from 67° to 90°, with overnight lows between 45° and 65°. The average high for September is 79° with an average low of 55°. 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 Colorado. See also: October | November | December.
