S
M
T
W
T
F
S
30
74°
72°
31
72°
69°
1
71°
66°
2
70°
64°
3
70°
63°
4
77°
61°
5
74°
62°
6
89°
71°
7
76°
70°
8
80°
70°
9
80°
72°
10
76°
73°
11
74°
72°
12
71°
69°
13
72°
68°
14
75°
65°
15
78°
65°
16
76°
63°
17
75°
64°
18
74°
64°
19
75°
67°
20
74°
67°
21
73°
68°
22
74°
67°
23
75°
66°
24
74°
67°
25
75°
65°
26
78°
67°
27
77°
64°
28
74°
59°
29
72°
62°
30
71°
63°
1
70°
63°
2
70°
61°
3
71°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Cardiff-by-the-Sea
Cardiff-by-the-Sea's September 2026 forecast shows daily high temperatures ranging from 70° to 78°, with overnight lows between 59° and 68°. The average high for September is 74° with an average low of 64°. 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 Cardiff-by-the-Sea. See also: October | November | December.
