S
M
T
W
T
F
S
26
90°
71°
27
90°
70°
28
89°
71°
29
90°
71°
30
89°
70°
31
90°
71°
1
91°
72°
2
90°
70°
3
90°
70°
4
89°
71°
5
89°
69°
6
87°
68°
7
87°
68°
8
88°
67°
9
87°
68°
10
84°
69°
11
87°
67°
12
90°
65°
13
87°
67°
14
86°
68°
15
90°
62°
16
90°
58°
17
79°
57°
18
78°
55°
19
76°
56°
20
77°
56°
21
77°
57°
22
78°
57°
23
76°
59°
24
78°
62°
25
83°
60°
26
80°
55°
27
75°
55°
28
77°
59°
29
82°
63°
30
85°
61°
31
87°
54°
1
82°
54°
2
75°
62°
3
78°
63°
4
85°
54°
5
85°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Saint Charles
Saint Charles's August 2026 forecast shows daily high temperatures ranging from 75° to 91°, with overnight lows between 51° and 72°. The average high for August is 84° 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 Saint Charles. See also: September | October | November.
