S
M
T
W
T
F
S
26
87°
69°
27
89°
68°
28
84°
69°
29
85°
69°
30
88°
70°
31
88°
70°
1
89°
69°
2
89°
70°
3
89°
62°
4
85°
63°
5
87°
66°
6
86°
64°
7
88°
63°
8
86°
62°
9
85°
62°
10
86°
63°
11
86°
69°
12
90°
68°
13
92°
66°
14
86°
66°
15
85°
67°
16
85°
65°
17
88°
64°
18
86°
62°
19
85°
61°
20
85°
61°
21
86°
63°
22
88°
69°
23
90°
66°
24
89°
65°
25
91°
66°
26
89°
67°
27
90°
66°
28
88°
67°
29
86°
66°
30
87°
60°
31
84°
58°
1
82°
57°
2
82°
58°
3
83°
61°
4
85°
64°
5
88°
62°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Alton
Alton's August 2026 forecast shows daily high temperatures ranging from 82° to 92°, with overnight lows between 57° and 70°. The average high for August is 87° with an average low of 65°. 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 Alton. See also: September | October | November.
