S
M
T
W
T
F
S
30
77°
53°
31
69°
50°
1
74°
47°
2
73°
52°
3
75°
47°
4
76°
52°
5
78°
46°
6
80°
55°
7
80°
51°
8
83°
47°
9
82°
52°
10
86°
48°
11
81°
50°
12
81°
52°
13
79°
52°
14
78°
54°
15
75°
56°
16
68°
53°
17
72°
52°
18
74°
45°
19
75°
43°
20
73°
39°
21
73°
44°
22
73°
43°
23
72°
44°
24
70°
44°
25
70°
39°
26
74°
44°
27
72°
43°
28
58°
48°
29
59°
47°
30
68°
42°
1
72°
42°
2
72°
44°
3
72°
44°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Flagstaff
Flagstaff's September 2026 forecast shows daily high temperatures ranging from 58° to 72°, with overnight lows between 42° and 48°. The average high for September is 67° with an average low of 45°. 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.
