S
M
T
W
T
F
S
30
90°
64°
31
93°
70°
1
93°
70°
2
95°
70°
3
97°
70°
4
97°
72°
5
91°
70°
6
86°
64°
7
88°
59°
8
90°
68°
9
90°
72°
10
79°
72°
11
82°
70°
12
81°
72°
13
90°
68°
14
79°
59°
15
91°
61°
16
93°
70°
17
95°
72°
18
86°
72°
19
88°
72°
20
91°
73°
21
88°
63°
22
66°
57°
23
68°
61°
24
70°
57°
25
73°
50°
26
N/A
27
75°
43°
28
77°
41°
29
81°
45°
30
86°
52°
1
90°
70°
2
82°
58°
3
69°
56°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Irvine
Irvine's September 2026 forecast shows daily high temperatures ranging from 69° to 90°, with overnight lows between 56° and 70°. The average high for September is 80° with an average low of 61°. 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 Irvine. See also: October | November | December.
