S
M
T
W
T
F
S
30
84°
66°
31
86°
60°
1
87°
57°
2
77°
61°
3
78°
64°
4
85°
63°
5
85°
55°
6
84°
55°
7
77°
62°
8
81°
62°
9
82°
55°
10
80°
60°
11
75°
56°
12
76°
53°
13
74°
51°
14
74°
52°
15
75°
55°
16
75°
59°
17
81°
60°
18
81°
60°
19
82°
58°
20
76°
57°
21
81°
58°
22
78°
50°
23
82°
49°
24
75°
47°
25
70°
48°
26
71°
48°
27
79°
56°
28
80°
57°
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 70° to 87°, with overnight lows between 47° and 66°. The average high for September is 79° with an average low of 56°. 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.
