S
M
T
W
T
F
S
30
87°
69°
31
87°
69°
1
86°
68°
2
87°
68°
3
85°
67°
4
84°
68°
5
83°
68°
6
84°
67°
7
86°
68°
8
87°
69°
9
88°
69°
10
88°
68°
11
87°
69°
12
87°
68°
13
86°
67°
14
80°
67°
15
82°
64°
16
83°
66°
17
86°
67°
18
87°
65°
19
86°
64°
20
86°
64°
21
85°
65°
22
83°
62°
23
82°
63°
24
85°
66°
25
86°
68°
26
86°
68°
27
87°
67°
28
88°
67°
29
87°
65°
30
85°
60°
1
83°
62°
2
78°
60°
3
76°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Tustin
Tustin's September 2026 forecast shows daily high temperatures ranging from 76° to 88°, with overnight lows between 57° and 69°. The average high for September is 85° with an average low of 66°. 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 Tustin. See also: October | November | December.
