S
M
T
W
T
F
S
30
91°
66°
31
91°
66°
1
90°
65°
2
91°
65°
3
89°
64°
4
88°
66°
5
87°
65°
6
88°
64°
7
90°
65°
8
91°
66°
9
91°
66°
10
90°
65°
11
91°
66°
12
91°
65°
13
89°
66°
14
84°
65°
15
86°
62°
16
87°
65°
17
90°
64°
18
84°
60°
19
86°
62°
20
88°
61°
21
89°
62°
22
90°
63°
23
89°
61°
24
90°
60°
25
89°
60°
26
88°
56°
27
83°
55°
28
81°
55°
29
81°
58°
30
82°
61°
1
86°
64°
2
89°
58°
3
89°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Foothill Ranch
Foothill Ranch's September 2026 forecast shows daily high temperatures ranging from 81° to 91°, with overnight lows between 54° and 66°. The average high for September is 88° with an average low of 62°. 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 Foothill Ranch. See also: October | November | December.