S
M
T
W
T
F
S
30
72°
59°
31
70°
58°
1
67°
57°
2
67°
56°
3
66°
56°
4
66°
56°
5
67°
55°
6
67°
57°
7
69°
58°
8
72°
52°
9
71°
53°
10
70°
57°
11
71°
51°
12
70°
50°
13
69°
56°
14
71°
55°
15
70°
48°
16
70°
47°
17
63°
48°
18
63°
53°
19
65°
48°
20
66°
45°
21
62°
49°
22
61°
52°
23
65°
52°
24
67°
51°
25
64°
52°
26
67°
52°
27
64°
44°
28
68°
43°
29
67°
43°
30
57°
44°
1
58°
45°
2
59°
43°
3
58°
48°
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 57° to 72°, with overnight lows between 43° and 59°. The average high for September is 66° with an average low of 51°. 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.
