S
M
T
W
T
F
S
30
92°
69°
31
94°
71°
1
95°
73°
2
95°
74°
3
93°
72°
4
92°
71°
5
91°
72°
6
97°
73°
7
96°
71°
8
99°
73°
9
97°
72°
10
96°
73°
11
93°
69°
12
93°
68°
13
92°
69°
14
90°
65°
15
85°
68°
16
86°
68°
17
87°
67°
18
88°
68°
19
88°
68°
20
85°
67°
21
84°
67°
22
86°
66°
23
88°
66°
24
88°
65°
25
90°
64°
26
89°
65°
27
90°
64°
28
90°
64°
29
89°
63°
30
90°
64°
1
89°
64°
2
87°
63°
3
86°
64°
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 84° to 99°, with overnight lows between 63° and 74°. The average high for September is 90° with an average low of 68°. 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.
