S
M
T
W
T
F
S
30
81°
72°
31
78°
69°
1
79°
67°
2
76°
66°
3
77°
63°
4
76°
65°
5
83°
65°
6
95°
73°
7
95°
74°
8
93°
74°
9
100°
72°
10
87°
70°
11
82°
71°
12
77°
68°
13
77°
67°
14
78°
66°
15
77°
68°
16
78°
70°
17
77°
69°
18
79°
68°
19
78°
69°
20
79°
70°
21
77°
67°
22
77°
66°
23
74°
66°
24
73°
64°
25
73°
65°
26
79°
68°
27
79°
67°
28
76°
65°
29
77°
67°
30
79°
68°
1
79°
69°
2
80°
68°
3
79°
68°
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 73° to 100°, with overnight lows between 64° and 72°. The average high for September is 79° with an average low of 68°. 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.
