S
M
T
W
T
F
S
30
75°
64°
31
76°
64°
1
75°
63°
2
74°
64°
3
74°
64°
4
75°
65°
5
74°
65°
6
75°
66°
7
75°
67°
8
76°
66°
9
74°
68°
10
75°
69°
11
78°
68°
12
79°
68°
13
79°
67°
14
78°
70°
15
80°
70°
16
80°
69°
17
79°
69°
18
81°
68°
19
80°
69°
20
80°
70°
21
79°
71°
22
81°
70°
23
81°
70°
24
80°
68°
25
75°
66°
26
72°
64°
27
74°
66°
28
73°
67°
29
76°
65°
30
74°
64°
1
72°
65°
2
72°
67°
3
72°
67°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in San Diego
San Diego's September 2026 forecast shows daily high temperatures ranging from 72° to 81°, with overnight lows between 63° and 71°. The average high for September is 76° with an average low of 67°. 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 San Diego. See also: October | November | December.
