S
M
T
W
T
F
S
30
95°
72°
31
94°
73°
1
84°
76°
2
91°
76°
3
94°
74°
4
92°
73°
5
92°
72°
6
91°
72°
7
93°
74°
8
94°
72°
9
93°
74°
10
93°
73°
11
90°
72°
12
94°
73°
13
95°
72°
14
95°
73°
15
95°
73°
16
94°
73°
17
93°
69°
18
92°
64°
19
98°
69°
20
97°
70°
21
96°
71°
22
98°
73°
23
93°
71°
24
92°
67°
25
91°
66°
26
93°
64°
27
89°
61°
28
90°
62°
29
90°
65°
30
88°
64°
1
86°
65°
2
83°
61°
3
87°
66°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Saint Louis
Saint Louis's September 2026 forecast shows daily high temperatures ranging from 83° to 98°, with overnight lows between 61° and 73°. The average high for September is 91° with an average low of 66°. 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 Louis. See also: October | November | December.
