S
M
T
W
T
F
S
30
77°
56°
31
77°
55°
1
76°
57°
2
78°
51°
3
74°
47°
4
67°
45°
5
66°
54°
6
67°
55°
7
74°
55°
8
73°
54°
9
74°
51°
10
70°
50°
11
73°
52°
12
73°
54°
13
72°
54°
14
73°
52°
15
73°
45°
16
66°
43°
17
65°
50°
18
67°
45°
19
65°
42°
20
65°
40°
21
59°
38°
22
59°
48°
23
61°
44°
24
61°
40°
25
58°
38°
26
59°
43°
27
60°
47°
28
66°
38°
29
65°
39°
30
57°
40°
1
58°
39°
2
59°
36°
3
56°
35°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in California
California's September 2026 forecast shows daily high temperatures ranging from 56° to 78°, with overnight lows between 35° and 57°. The average high for September is 67° with an average low of 47°. 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 California. See also: October | November | December.