S
M
T
W
T
F
S
26
95°
63°
27
97°
63°
28
98°
62°
29
94°
61°
30
96°
62°
31
98°
64°
1
97°
63°
2
97°
64°
3
98°
64°
4
98°
63°
5
97°
64°
6
98°
64°
7
98°
63°
8
97°
64°
9
98°
63°
10
98°
62°
11
92°
62°
12
94°
61°
13
95°
59°
14
92°
61°
15
92°
63°
16
95°
63°
17
97°
61°
18
97°
63°
19
96°
62°
20
98°
63°
21
93°
62°
22
92°
63°
23
93°
63°
24
93°
62°
25
94°
60°
26
92°
58°
27
90°
58°
28
91°
62°
29
92°
63°
30
92°
63°
31
94°
61°
1
93°
61°
2
93°
59°
3
94°
59°
4
92°
56°
5
92°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Simi Valley
Simi Valley's August 2026 forecast shows daily high temperatures ranging from 90° to 98°, with overnight lows between 56° and 64°. The average high for August is 95° 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 August weather will actually feel in Simi Valley. See also: September | October | November.
