S
M
T
W
T
F
S
30
85°
58°
31
83°
53°
1
79°
52°
2
77°
53°
3
77°
52°
4
78°
54°
5
77°
52°
6
76°
51°
7
76°
52°
8
77°
55°
9
76°
52°
10
74°
51°
11
75°
52°
12
75°
51°
13
76°
52°
14
75°
51°
15
73°
52°
16
75°
49°
17
74°
48°
18
74°
49°
19
72°
54°
20
74°
53°
21
73°
46°
22
70°
46°
23
Hist. Avg.
72°
47°
24
Hist. Avg.
72°
46°
25
Hist. Avg.
71°
46°
26
Hist. Avg.
71°
46°
27
Hist. Avg.
70°
45°
28
Hist. Avg.
70°
45°
29
Hist. Avg.
70°
45°
30
Hist. Avg.
69°
44°
1
Hist. Avg.
69°
44°
2
Hist. Avg.
68°
44°
3
Hist. Avg.
68°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Montana
Montana's September 2026 forecast shows daily high temperatures ranging from 70° to 85°, with overnight lows between 46° and 58°. The average high for September is 76° with an average low of 52°. 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 Montana. See also: October | November | December.
