S
M
T
W
T
F
S
30
77°
70°
31
74°
71°
1
74°
71°
2
75°
70°
3
75°
71°
4
78°
71°
5
80°
70°
6
80°
71°
7
79°
71°
8
80°
70°
9
79°
70°
10
80°
71°
11
80°
70°
12
79°
69°
13
80°
70°
14
81°
71°
15
80°
70°
16
81°
70°
17
80°
69°
18
76°
70°
19
76°
68°
20
77°
69°
21
76°
67°
22
73°
65°
23
73°
63°
24
79°
67°
25
79°
69°
26
78°
69°
27
79°
67°
28
72°
64°
29
73°
67°
30
78°
67°
1
79°
68°
2
79°
65°
3
78°
62°
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 62° and 71°. The average high for September is 78° with an average low of 69°. 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.
