S
M
T
W
T
F
S
30
82°
73°
31
80°
69°
1
79°
68°
2
79°
65°
3
78°
66°
4
78°
65°
5
85°
65°
6
79°
69°
7
92°
75°
8
99°
75°
9
102°
78°
10
89°
77°
11
83°
74°
12
80°
72°
13
79°
71°
14
79°
69°
15
78°
69°
16
78°
68°
17
79°
70°
18
78°
66°
19
81°
65°
20
80°
67°
21
80°
64°
22
82°
62°
23
86°
66°
24
88°
67°
25
87°
68°
26
88°
67°
27
88°
67°
28
87°
65°
29
86°
67°
30
85°
66°
1
85°
65°
2
79°
63°
3
80°
65°
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 79° to 88°, with overnight lows between 62° and 68°. The average high for September is 84° 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.
