S
M
T
W
T
F
S
26
80°
66°
27
81°
67°
28
86°
67°
29
87°
66°
30
86°
67°
31
84°
67°
1
85°
66°
2
86°
67°
3
86°
67°
4
85°
66°
5
83°
66°
6
84°
67°
7
86°
64°
8
79°
60°
9
78°
59°
10
78°
60°
11
79°
66°
12
79°
66°
13
83°
67°
14
84°
67°
15
84°
65°
16
78°
62°
17
79°
56°
18
79°
57°
19
81°
65°
20
84°
63°
21
85°
64°
22
84°
63°
23
84°
61°
24
78°
59°
25
78°
59°
26
77°
57°
27
77°
58°
28
78°
58°
29
78°
58°
30
83°
58°
31
84°
62°
1
84°
62°
2
82°
59°
3
82°
53°
4
76°
52°
5
75°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Helena
Helena's August 2026 forecast shows daily high temperatures ranging from 75° to 87°, with overnight lows between 52° and 67°. The average high for August is 82° with an average low of 62°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Helena. See also: September | October | November.