S
M
T
W
T
F
S
30
95°
63°
31
100°
65°
1
100°
70°
2
101°
73°
3
100°
73°
4
100°
73°
5
102°
74°
6
91°
73°
7
88°
62°
8
95°
59°
9
94°
70°
10
81°
69°
11
85°
66°
12
93°
65°
13
88°
67°
14
88°
62°
15
100°
69°
16
95°
73°
17
98°
71°
18
99°
72°
19
97°
70°
20
93°
70°
21
73°
67°
22
N/A
23
72°
57°
24
71°
58°
25
73°
55°
26
69°
56°
27
N/A
28
N/A
29
86°
49°
30
94°
65°
1
92°
68°
2
73°
54°
3
76°
49°
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 ° to °, with overnight lows between ° and °. The average high for September is ° with an average low of °. 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.
