S
M
T
W
T
F
S
30
81°
52°
31
75°
64°
1
90°
66°
2
71°
67°
3
88°
66°
4
82°
68°
5
78°
59°
6
79°
55°
7
79°
54°
8
82°
61°
9
88°
69°
10
85°
60°
11
76°
54°
12
77°
59°
13
82°
60°
14
78°
56°
15
81°
61°
16
80°
56°
17
75°
57°
18
76°
54°
19
77°
53°
20
78°
55°
21
77°
58°
22
69°
57°
23
70°
57°
24
71°
56°
25
71°
56°
26
76°
54°
27
72°
51°
28
74°
55°
29
75°
56°
30
76°
56°
1
75°
55°
2
73°
54°
3
73°
52°
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 69° to 88°, with overnight lows between 51° and 69°. The average high for September is 77° with an average low of 57°. 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.
