S
M
T
W
T
F
S
30
84°
59°
31
78°
59°
1
78°
60°
2
77°
59°
3
78°
64°
4
78°
58°
5
82°
59°
6
77°
58°
7
76°
57°
8
77°
56°
9
76°
56°
10
79°
60°
11
80°
62°
12
74°
61°
13
75°
61°
14
74°
54°
15
72°
53°
16
Hist. Avg.
79°
58°
17
Hist. Avg.
79°
58°
18
Hist. Avg.
79°
57°
19
Hist. Avg.
78°
57°
20
Hist. Avg.
78°
56°
21
Hist. Avg.
77°
56°
22
Hist. Avg.
77°
56°
23
Hist. Avg.
77°
55°
24
Hist. Avg.
76°
55°
25
Hist. Avg.
76°
54°
26
Hist. Avg.
75°
54°
27
Hist. Avg.
75°
53°
28
Hist. Avg.
75°
53°
29
Hist. Avg.
74°
52°
30
Hist. Avg.
74°
52°
1
Hist. Avg.
73°
52°
2
Hist. Avg.
73°
51°
3
Hist. Avg.
73°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Great Falls
Great Falls's September 2026 forecast shows daily high temperatures ranging from 72° to 84°, with overnight lows between 53° and 64°. The average high for September is 77° with an average low of 59°. 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 Great Falls. See also: October | November | December.
