S
M
T
W
T
F
S
30
81°
50°
31
78°
48°
1
74°
48°
2
74°
49°
3
75°
51°
4
79°
50°
5
76°
47°
6
78°
48°
7
79°
49°
8
80°
49°
9
79°
47°
10
78°
47°
11
72°
46°
12
75°
46°
13
76°
47°
14
77°
47°
15
75°
45°
16
72°
45°
17
71°
44°
18
71°
45°
19
76°
38°
20
74°
43°
21
75°
44°
22
Hist. Avg.
72°
40°
23
Hist. Avg.
72°
40°
24
Hist. Avg.
72°
39°
25
Hist. Avg.
71°
39°
26
Hist. Avg.
71°
39°
27
Hist. Avg.
71°
38°
28
Hist. Avg.
70°
38°
29
Hist. Avg.
70°
37°
30
Hist. Avg.
70°
37°
1
Hist. Avg.
69°
37°
2
Hist. Avg.
69°
36°
3
Hist. Avg.
68°
36°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Flagstaff
Flagstaff's September 2026 forecast shows daily high temperatures ranging from 71° to 81°, with overnight lows between 38° and 51°. The average high for September is 76° with an average low of 47°. 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 Flagstaff. See also: October | November | December.
