S
M
T
W
T
F
S
30
98°
77°
31
97°
75°
1
99°
67°
2
99°
67°
3
97°
75°
4
96°
70°
5
98°
70°
6
99°
72°
7
97°
75°
8
100°
72°
9
96°
66°
10
91°
69°
11
83°
61°
12
85°
61°
13
87°
63°
14
85°
62°
15
86°
60°
16
76°
58°
17
86°
62°
18
77°
54°
19
81°
58°
20
82°
59°
21
77°
58°
22
82°
58°
23
82°
58°
24
81°
57°
25
79°
55°
26
70°
48°
27
69°
45°
28
68°
44°
29
69°
49°
30
74°
45°
1
73°
52°
2
71°
50°
3
66°
49°
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 66° to 100°, with overnight lows between 44° and 75°. The average high for September is 83° with an average low of 59°. 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.
