S
M
T
W
T
F
S
30
83°
58°
31
84°
62°
1
84°
62°
2
82°
59°
3
82°
53°
4
76°
52°
5
75°
54°
6
77°
61°
7
82°
60°
8
82°
59°
9
75°
55°
10
76°
60°
11
78°
59°
12
82°
60°
13
82°
59°
14
81°
59°
15
81°
58°
16
80°
58°
17
75°
50°
18
77°
49°
19
71°
47°
20
71°
46°
21
69°
46°
22
70°
53°
23
71°
48°
24
73°
46°
25
69°
53°
26
73°
53°
27
70°
54°
28
76°
53°
29
75°
51°
30
74°
49°
1
70°
50°
2
73°
51°
3
69°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Helena
Helena's September 2026 forecast shows daily high temperatures ranging from 69° to 84°, with overnight lows between 46° and 62°. The average high for September is 76° with an average low of 54°. 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 Helena. See also: October | November | December.
