S
M
T
W
T
F
S
26
85°
62°
27
87°
62°
28
78°
65°
29
76°
64°
30
79°
64°
31
86°
59°
1
85°
59°
2
77°
68°
3
84°
61°
4
86°
56°
5
85°
63°
6
88°
69°
7
84°
70°
8
84°
69°
9
88°
65°
10
82°
64°
11
81°
66°
12
82°
67°
13
83°
66°
14
84°
66°
15
84°
61°
16
72°
67°
17
87°
69°
18
83°
62°
19
84°
57°
20
74°
59°
21
76°
54°
22
79°
53°
23
78°
55°
24
73°
54°
25
78°
56°
26
83°
55°
27
87°
62°
28
83°
54°
29
82°
61°
30
87°
68°
31
87°
66°
1
90°
72°
2
90°
66°
3
86°
64°
4
85°
61°
5
80°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Lewistown
Lewistown's August 2026 forecast shows daily high temperatures ranging from 80° to 90°, with overnight lows between 54° and 72°. The average high for August is 86° with an average low of 63°. 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 Lewistown. See also: September | October | November.
