S
M
T
W
T
F
S
30
85°
66°
31
86°
64°
1
86°
61°
2
82°
63°
3
81°
57°
4
78°
56°
5
77°
55°
6
79°
62°
7
82°
55°
8
79°
56°
9
78°
62°
10
77°
61°
11
82°
61°
12
83°
60°
13
83°
60°
14
84°
61°
15
84°
61°
16
73°
55°
17
74°
59°
18
Hist. Avg.
79°
53°
19
Hist. Avg.
79°
53°
20
Hist. Avg.
79°
53°
21
Hist. Avg.
78°
52°
22
Hist. Avg.
78°
52°
23
Hist. Avg.
78°
52°
24
Hist. Avg.
77°
51°
25
Hist. Avg.
77°
51°
26
Hist. Avg.
76°
50°
27
Hist. Avg.
76°
50°
28
Hist. Avg.
76°
50°
29
Hist. Avg.
75°
49°
30
Hist. Avg.
75°
49°
1
Hist. Avg.
74°
48°
2
Hist. Avg.
74°
48°
3
Hist. Avg.
74°
48°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Helena
Helena's September 2026 forecast shows daily high temperatures ranging from 73° to 86°, with overnight lows between 55° and 66°. The average high for September is 81° with an average low of 60°. 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.
