S
M
T
W
T
F
S
30
88°
48°
31
92°
51°
1
75°
54°
2
60°
52°
3
66°
51°
4
68°
48°
5
75°
48°
6
68°
53°
7
80°
46°
8
83°
53°
9
90°
55°
10
85°
51°
11
79°
44°
12
59°
42°
13
73°
40°
14
80°
42°
15
85°
44°
16
83°
48°
17
83°
47°
18
86°
45°
19
84°
44°
20
85°
46°
21
82°
43°
22
76°
42°
23
76°
44°
24
79°
45°
25
80°
46°
26
74°
46°
27
74°
41°
28
73°
39°
29
72°
36°
30
73°
39°
1
81°
45°
2
82°
45°
3
82°
46°
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 59° to 90°, with overnight lows between 36° and 55°. The average high for September is 79° with an average low of 45°. 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.
