S
M
T
W
T
F
S
30
83°
70°
31
82°
70°
1
83°
69°
2
83°
70°
3
78°
67°
4
78°
68°
5
83°
70°
6
83°
70°
7
84°
69°
8
82°
70°
9
81°
69°
10
81°
70°
11
80°
69°
12
83°
71°
13
83°
70°
14
84°
69°
15
83°
71°
16
82°
69°
17
84°
69°
18
84°
67°
19
81°
65°
20
75°
67°
21
77°
69°
22
82°
68°
23
77°
67°
24
75°
68°
25
78°
68°
26
82°
67°
27
82°
68°
28
81°
66°
29
75°
65°
30
74°
62°
1
75°
65°
2
76°
66°
3
81°
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 84°, with overnight lows between 62° and 71°. The average high for September is 80° with an average low of 68°. 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.
