S
M
T
W
T
F
S
26
84°
64°
27
87°
68°
28
89°
71°
29
84°
69°
30
85°
68°
31
88°
65°
1
87°
65°
2
81°
74°
3
89°
74°
4
86°
72°
5
82°
72°
6
90°
72°
7
89°
71°
8
85°
68°
9
87°
69°
10
90°
72°
11
89°
68°
12
86°
69°
13
83°
66°
14
84°
65°
15
85°
67°
16
84°
65°
17
86°
69°
18
86°
68°
19
85°
69°
20
86°
67°
21
84°
66°
22
84°
68°
23
86°
69°
24
87°
68°
25
86°
68°
26
84°
67°
27
80°
67°
28
82°
66°
29
81°
65°
30
82°
66°
31
82°
66°
1
83°
64°
2
76°
59°
3
75°
59°
4
75°
60°
5
76°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Great Falls
Great Falls's August 2026 forecast shows daily high temperatures ranging from 75° to 90°, with overnight lows between 58° and 72°. The average high for August is 84° with an average low of 67°. 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 Great Falls. See also: September | October | November.