S
M
T
W
T
F
S
30
71°
42°
31
82°
37°
1
88°
45°
2
66°
48°
3
68°
50°
4
67°
49°
5
69°
46°
6
74°
51°
7
66°
50°
8
66°
45°
9
75°
46°
10
76°
48°
11
77°
48°
12
74°
46°
13
73°
45°
14
76°
46°
15
74°
44°
16
80°
48°
17
65°
41°
18
66°
43°
19
62°
37°
20
64°
45°
21
64°
43°
22
68°
47°
23
68°
41°
24
60°
36°
25
60°
34°
26
61°
37°
27
65°
39°
28
71°
41°
29
72°
42°
30
70°
42°
1
71°
43°
2
70°
44°
3
71°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Missoula
Missoula's September 2026 forecast shows daily high temperatures ranging from 60° to 80°, with overnight lows between 34° and 51°. The average high for September is 69° with an average low of 44°. 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 Missoula. See also: October | November | December.
