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
75°
55°
15
74°
55°
16
73°
54°
17
71°
49°
18
72°
47°
19
71°
45°
20
74°
45°
21
72°
46°
22
69°
45°
23
69°
47°
24
69°
45°
25
72°
46°
26
71°
44°
27
75°
44°
28
71°
44°
29
71°
43°
30
70°
43°
1
73°
42°
2
72°
43°
3
68°
41°
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 68° to 75°, with overnight lows between 41° and 55°. The average high for September is 72° with an average low of 46°. 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.
