S
M
T
W
T
F
S
26
96°
76°
27
96°
77°
28
95°
77°
29
95°
76°
30
96°
77°
31
95°
75°
1
92°
74°
2
88°
74°
3
90°
75°
4
90°
75°
5
93°
74°
6
93°
75°
7
92°
74°
8
93°
74°
9
93°
73°
10
92°
74°
11
93°
74°
12
93°
73°
13
92°
74°
14
93°
72°
15
94°
73°
16
93°
70°
17
88°
73°
18
93°
72°
19
92°
70°
20
92°
67°
21
87°
65°
22
87°
65°
23
86°
66°
24
87°
66°
25
89°
65°
26
89°
65°
27
92°
66°
28
93°
69°
29
93°
71°
30
92°
71°
31
93°
70°
1
93°
71°
2
92°
68°
3
91°
66°
4
88°
68°
5
90°
68°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in St. Charles
St. Charles's August 2026 forecast shows daily high temperatures ranging from 86° to 96°, with overnight lows between 65° and 77°. The average high for August is 92° with an average low of 71°. 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 St. Charles. See also: September | October | November.
