S
M
T
W
T
F
S
26
91°
74°
27
92°
73°
28
91°
73°
29
90°
72°
30
87°
71°
31
85°
70°
1
83°
69°
2
84°
71°
3
88°
70°
4
87°
66°
5
87°
70°
6
86°
68°
7
88°
71°
8
82°
70°
9
82°
68°
10
83°
67°
11
84°
67°
12
85°
69°
13
87°
70°
14
88°
71°
15
89°
72°
16
91°
71°
17
89°
70°
18
90°
71°
19
90°
71°
20
89°
69°
21
81°
60°
22
80°
61°
23
80°
61°
24
80°
62°
25
82°
67°
26
87°
68°
27
89°
69°
28
90°
70°
29
90°
67°
30
89°
60°
31
80°
63°
1
81°
63°
2
87°
68°
3
89°
69°
4
89°
68°
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 80° to 92°, with overnight lows between 60° and 74°. The average high for August is 86° with an average low of 68°. 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.
