S
M
T
W
T
F
S
30
78°
56°
31
79°
60°
1
84°
54°
2
79°
52°
3
76°
52°
4
75°
51°
5
77°
56°
6
83°
61°
7
86°
63°
8
87°
58°
9
82°
52°
10
77°
53°
11
78°
61°
12
81°
53°
13
85°
49°
14
75°
49°
15
75°
53°
16
76°
58°
17
82°
56°
18
81°
49°
19
75°
57°
20
81°
57°
21
82°
56°
22
83°
57°
23
83°
57°
24
81°
56°
25
82°
57°
26
81°
57°
27
82°
56°
28
82°
55°
29
81°
55°
30
81°
56°
1
80°
46°
2
82°
43°
3
78°
44°
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 75° to 87°, with overnight lows between 43° and 63°. The average high for September is 80° with an average low of 54°. 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.
