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
79°
68°
17
80°
65°
18
82°
65°
19
82°
66°
20
80°
69°
21
77°
67°
22
78°
68°
23
82°
67°
24
81°
66°
25
80°
65°
26
81°
66°
27
81°
65°
28
82°
66°
29
79°
64°
30
76°
64°
1
74°
62°
2
76°
63°
3
77°
66°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Irvine
Irvine's September 2026 forecast shows daily high temperatures ranging from 74° to 82°, with overnight lows between 62° and 69°. The average high for September is 79° 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 Irvine. See also: October | November | December.
