S
M
T
W
T
F
S
27
N/A
28
75°
67°
29
78°
63°
30
76°
68°
1
77°
62°
2
86°
62°
3
97°
70°
4
96°
71°
5
96°
72°
6
91°
69°
7
87°
68°
8
85°
70°
9
85°
70°
10
81°
69°
11
74°
68°
12
72°
63°
13
75°
64°
14
77°
63°
15
78°
65°
16
81°
66°
17
83°
66°
18
82°
65°
19
73°
60°
20
76°
63°
21
75°
64°
22
76°
63°
23
76°
63°
24
75°
62°
25
76°
63°
26
75°
63°
27
71°
58°
28
66°
55°
29
66°
54°
30
67°
55°
31
67°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
October Weather in Costa Mesa
Costa Mesa's October 2026 forecast shows daily high temperatures ranging from 66° to 91°, with overnight lows between 54° and 70°. The average high for October is 77° with an average low of 63°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how October weather will actually feel in Costa Mesa. See also: November | December | January.
