S
M
T
W
T
F
S
30
85°
61°
31
87°
54°
1
82°
54°
2
75°
62°
3
78°
63°
4
85°
54°
5
85°
51°
6
75°
54°
7
75°
59°
8
80°
58°
9
80°
52°
10
74°
56°
11
73°
54°
12
73°
49°
13
72°
49°
14
72°
51°
15
73°
56°
16
74°
58°
17
81°
58°
18
82°
56°
19
81°
52°
20
74°
53°
21
80°
54°
22
72°
46°
23
78°
46°
24
67°
45°
25
69°
45°
26
67°
44°
27
67°
42°
28
Hist. Avg.
72°
47°
29
Hist. Avg.
72°
46°
30
Hist. Avg.
72°
46°
1
Hist. Avg.
71°
46°
2
Hist. Avg.
71°
45°
3
Hist. Avg.
70°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Saint Charles
Saint Charles's September 2026 forecast shows daily high temperatures ranging from 67° to 87°, with overnight lows between 42° and 63°. The average high for September is 76° with an average low of 53°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Saint Charles. See also: October | November | December.
