S
M
T
W
T
F
S
30
88°
64°
31
83°
62°
1
82°
62°
2
81°
63°
3
82°
66°
4
83°
65°
5
88°
66°
6
81°
67°
7
81°
61°
8
80°
62°
9
80°
61°
10
81°
59°
11
79°
59°
12
79°
60°
13
78°
59°
14
77°
64°
15
79°
63°
16
80°
62°
17
82°
60°
18
82°
59°
19
81°
60°
20
84°
56°
21
76°
56°
22
Hist. Avg.
79°
55°
23
Hist. Avg.
78°
54°
24
Hist. Avg.
78°
54°
25
Hist. Avg.
78°
54°
26
Hist. Avg.
77°
53°
27
Hist. Avg.
77°
53°
28
Hist. Avg.
77°
53°
29
Hist. Avg.
76°
52°
30
Hist. Avg.
76°
52°
1
Hist. Avg.
76°
52°
2
Hist. Avg.
75°
51°
3
Hist. Avg.
75°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in St. Louis
St. Louis's September 2026 forecast shows daily high temperatures ranging from 76° to 88°, with overnight lows between 56° and 67°. The average high for September is 81° with an average low of 62°. 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. Louis. See also: October | November | December.
