S
M
T
W
T
F
S
30
83°
54°
31
82°
54°
1
81°
50°
2
79°
50°
3
78°
54°
4
79°
52°
5
82°
52°
6
83°
51°
7
77°
50°
8
78°
53°
9
77°
52°
10
79°
46°
11
78°
49°
12
82°
52°
13
82°
47°
14
Hist. Avg.
80°
45°
15
Hist. Avg.
80°
45°
16
Hist. Avg.
79°
44°
17
Hist. Avg.
79°
44°
18
Hist. Avg.
78°
44°
19
Hist. Avg.
78°
43°
20
Hist. Avg.
77°
43°
21
Hist. Avg.
77°
42°
22
Hist. Avg.
76°
42°
23
Hist. Avg.
76°
42°
24
Hist. Avg.
75°
41°
25
Hist. Avg.
75°
41°
26
Hist. Avg.
74°
40°
27
Hist. Avg.
74°
40°
28
Hist. Avg.
73°
40°
29
Hist. Avg.
73°
39°
30
Hist. Avg.
72°
39°
1
Hist. Avg.
72°
38°
2
Hist. Avg.
72°
38°
3
Hist. Avg.
71°
38°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Fort Collins
Fort Collins's September 2026 forecast shows daily high temperatures ranging from 77° to 83°, with overnight lows between 46° and 54°. The average high for September is 80° with an average low of 51°. 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 Fort Collins. See also: October | November | December.
