S
M
T
W
T
F
S
26
79°
64°
27
80°
66°
28
76°
66°
29
76°
65°
30
78°
65°
31
80°
66°
1
80°
65°
2
79°
66°
3
81°
65°
4
82°
65°
5
78°
60°
6
77°
63°
7
76°
59°
8
75°
58°
9
75°
57°
10
76°
58°
11
79°
64°
12
82°
64°
13
82°
64°
14
81°
58°
15
76°
59°
16
77°
64°
17
76°
62°
18
76°
58°
19
77°
57°
20
76°
61°
21
77°
59°
22
80°
61°
23
80°
60°
24
81°
62°
25
81°
62°
26
82°
63°
27
81°
62°
28
80°
63°
29
81°
63°
30
80°
61°
31
77°
54°
1
74°
54°
2
74°
55°
3
75°
54°
4
75°
55°
5
74°
55°
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 74° to 82°, with overnight lows between 54° and 66°. The average high for August is 78° with an average low of 61°. 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.
