S
M
T
W
T
F
S
30
90°
77°
31
91°
78°
1
91°
75°
2
87°
71°
3
86°
70°
4
88°
74°
5
87°
73°
6
87°
73°
7
88°
73°
8
87°
76°
9
85°
72°
10
85°
72°
11
84°
70°
12
83°
71°
13
82°
71°
14
83°
70°
15
80°
69°
16
81°
70°
17
81°
69°
18
80°
70°
19
80°
70°
20
81°
69°
21
80°
70°
22
81°
70°
23
81°
69°
24
80°
70°
25
80°
70°
26
81°
69°
27
80°
70°
28
81°
70°
29
80°
69°
30
81°
69°
1
82°
70°
2
81°
70°
3
82°
69°
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 80° to 88°, with overnight lows between 69° and 76°. The average high for September is 83° with an average low of 71°. 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.
