S
M
T
W
T
F
S
30
95°
65°
31
97°
64°
1
99°
71°
2
99°
73°
3
99°
74°
4
100°
72°
5
102°
73°
6
90°
74°
7
89°
62°
8
93°
59°
9
94°
69°
10
82°
68°
11
81°
68°
12
89°
67°
13
89°
68°
14
92°
70°
15
96°
68°
16
90°
68°
17
78°
62°
18
76°
57°
19
77°
59°
20
78°
56°
21
76°
53°
22
76°
57°
23
78°
54°
24
83°
61°
25
83°
60°
26
82°
59°
27
82°
60°
28
81°
59°
29
79°
59°
30
80°
57°
1
79°
52°
2
79°
58°
3
80°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in St. Peters
St. Peters's September 2026 forecast shows daily high temperatures ranging from 76° to 96°, with overnight lows between 52° and 70°. The average high for September is 82° with an average low of 61°. 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. Peters. See also: October | November | December.
