S
M
T
W
T
F
S
30
84°
66°
31
85°
67°
1
89°
68°
2
89°
69°
3
88°
70°
4
87°
65°
5
84°
63°
6
83°
64°
7
84°
65°
8
84°
68°
9
83°
66°
10
84°
67°
11
87°
66°
12
88°
67°
13
87°
67°
14
87°
66°
15
88°
67°
16
87°
67°
17
86°
66°
18
86°
64°
19
85°
63°
20
85°
59°
21
82°
63°
22
80°
63°
23
81°
62°
24
85°
57°
25
83°
57°
26
80°
62°
27
83°
61°
28
78°
57°
29
82°
60°
30
82°
60°
1
81°
58°
2
82°
59°
3
83°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Prospect
Prospect's September 2026 forecast shows daily high temperatures ranging from 78° to 89°, with overnight lows between 57° and 70°. The average high for September is 84° with an average low of 64°. 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 Prospect. See also: October | November | December.
