S
M
T
W
T
F
S
30
73°
56°
31
74°
63°
1
75°
64°
2
76°
65°
3
77°
58°
4
76°
53°
5
73°
55°
6
71°
53°
7
71°
56°
8
75°
57°
9
75°
62°
10
78°
54°
11
73°
54°
12
70°
60°
13
70°
52°
14
71°
52°
15
67°
58°
16
69°
56°
17
68°
57°
18
71°
50°
19
69°
51°
20
68°
50°
21
71°
49°
22
67°
54°
23
69°
55°
24
73°
58°
25
74°
57°
26
73°
57°
27
72°
58°
28
75°
54°
29
71°
49°
30
67°
56°
1
70°
55°
2
73°
46°
3
70°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in St. Clair
St. Clair's September 2026 forecast shows daily high temperatures ranging from 67° to 78°, with overnight lows between 45° and 65°. The average high for September is 72° with an average low of 55°. 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 St. Clair. See also: October | November | December.
