S
M
T
W
T
F
S
30
79°
62°
31
81°
63°
1
82°
61°
2
76°
59°
3
76°
59°
4
77°
60°
5
81°
61°
6
81°
61°
7
80°
60°
8
82°
62°
9
81°
60°
10
74°
59°
11
80°
61°
12
81°
61°
13
80°
60°
14
71°
49°
15
69°
49°
16
70°
54°
17
72°
53°
18
79°
58°
19
79°
51°
20
78°
49°
21
68°
45°
22
67°
49°
23
66°
53°
24
67°
52°
25
68°
54°
26
73°
55°
27
75°
55°
28
76°
54°
29
76°
55°
30
75°
50°
1
75°
44°
2
71°
41°
3
60°
40°
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 60° to 82°, with overnight lows between 40° and 63°. The average high for September is 75° with an average low of 55°. 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.
