S
M
T
W
T
F
S
30
81°
66°
31
89°
59°
1
86°
53°
2
86°
61°
3
90°
67°
4
86°
64°
5
84°
62°
6
85°
64°
7
85°
64°
8
86°
61°
9
78°
54°
10
81°
47°
11
87°
63°
12
71°
49°
13
70°
42°
14
62°
41°
15
70°
45°
16
68°
52°
17
75°
57°
18
65°
60°
19
70°
57°
20
67°
52°
21
68°
51°
22
69°
53°
23
68°
53°
24
72°
54°
25
74°
55°
26
75°
56°
27
72°
54°
28
63°
52°
29
66°
51°
30
68°
47°
1
68°
50°
2
64°
50°
3
68°
48°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in St. Joseph
St. Joseph's September 2026 forecast shows daily high temperatures ranging from 63° to 75°, with overnight lows between 45° and 60°. The average high for September is 69° with an average low of 52°. 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. Joseph. See also: October | November | December.
