S
M
T
W
T
F
S
30
80°
62°
31
74°
63°
1
77°
62°
2
77°
55°
3
72°
53°
4
73°
54°
5
75°
57°
6
76°
59°
7
80°
61°
8
80°
60°
9
79°
59°
10
77°
60°
11
71°
54°
12
71°
52°
13
72°
50°
14
71°
49°
15
70°
48°
16
71°
46°
17
69°
48°
18
69°
46°
19
67°
44°
20
67°
45°
21
68°
45°
22
68°
46°
23
70°
48°
24
75°
53°
25
76°
55°
26
76°
54°
27
67°
47°
28
75°
53°
29
67°
43°
30
67°
52°
1
68°
47°
2
74°
41°
3
72°
39°
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 67° to 80°, with overnight lows between 39° and 63°. The average high for September is 73° 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.
