S
M
T
W
T
F
S
30
92°
62°
31
93°
60°
1
95°
58°
2
94°
57°
3
91°
56°
4
90°
57°
5
89°
57°
6
89°
59°
7
91°
60°
8
93°
57°
9
91°
56°
10
90°
57°
11
89°
59°
12
90°
61°
13
92°
62°
14
95°
61°
15
95°
62°
16
94°
64°
17
95°
62°
18
95°
62°
19
94°
63°
20
93°
62°
21
92°
59°
22
91°
58°
23
88°
60°
24
90°
59°
25
93°
61°
26
87°
59°
27
89°
55°
28
Hist. Avg.
87°
56°
29
Hist. Avg.
87°
56°
30
Hist. Avg.
86°
56°
1
Hist. Avg.
86°
56°
2
Hist. Avg.
86°
56°
3
Hist. Avg.
85°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Simi Valley
Simi Valley's September 2026 forecast shows daily high temperatures ranging from 87° to 95°, with overnight lows between 55° and 64°. The average high for September is 92° with an average low of 59°. 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 Simi Valley. See also: October | November | December.
