S
M
T
W
T
F
S
30
96°
65°
31
98°
72°
1
100°
74°
2
101°
72°
3
100°
72°
4
102°
73°
5
102°
73°
6
105°
75°
7
101°
73°
8
102°
70°
9
99°
73°
10
100°
73°
11
98°
74°
12
94°
72°
13
98°
73°
14
100°
75°
15
100°
73°
16
100°
72°
17
99°
73°
18
100°
70°
19
101°
71°
20
100°
72°
21
99°
73°
22
94°
70°
23
84°
60°
24
80°
56°
25
88°
59°
26
88°
59°
27
90°
64°
28
89°
61°
29
94°
65°
30
96°
69°
1
92°
72°
2
89°
68°
3
76°
64°
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 76° to 96°, with overnight lows between 64° and 72°. The average high for September is 89° with an average low of 68°. 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.
