S
M
T
W
T
F
S
30
84°
61°
31
86°
62°
1
80°
57°
2
80°
56°
3
81°
55°
4
79°
54°
5
79°
56°
6
82°
61°
7
82°
58°
8
81°
55°
9
79°
54°
10
80°
56°
11
83°
60°
12
84°
60°
13
84°
59°
14
83°
60°
15
84°
59°
16
82°
59°
17
83°
58°
18
82°
58°
19
81°
57°
20
80°
57°
21
81°
51°
22
78°
49°
23
75°
54°
24
74°
56°
25
Hist. Avg.
76°
49°
26
Hist. Avg.
76°
49°
27
Hist. Avg.
75°
48°
28
Hist. Avg.
75°
48°
29
Hist. Avg.
74°
48°
30
Hist. Avg.
74°
47°
1
Hist. Avg.
73°
47°
2
Hist. Avg.
73°
46°
3
Hist. Avg.
73°
46°
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 74° to 86°, with overnight lows between 49° and 62°. The average high for September is 81° with an average low of 57°. 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.
