S
M
T
W
T
F
S
26
89°
63°
27
93°
60°
28
90°
61°
29
90°
63°
30
93°
64°
31
100°
60°
1
93°
67°
2
80°
58°
3
81°
54°
4
88°
54°
5
95°
57°
6
98°
59°
7
99°
62°
8
101°
66°
9
96°
66°
10
95°
65°
11
96°
67°
12
94°
63°
13
92°
61°
14
93°
63°
15
97°
64°
16
96°
63°
17
91°
62°
18
96°
64°
19
96°
65°
20
95°
66°
21
90°
59°
22
89°
61°
23
90°
63°
24
94°
64°
25
95°
65°
26
95°
66°
27
94°
64°
28
94°
64°
29
92°
63°
30
86°
61°
31
84°
61°
1
87°
63°
2
81°
60°
3
81°
59°
4
86°
58°
5
88°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Lewiston
Lewiston's August 2026 forecast shows daily high temperatures ranging from 81° to 101°, with overnight lows between 58° and 67°. The average high for August is 92° 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 Lewiston. See also: September | October | November.