S
M
T
W
T
F
S
27
N/A
28
75°
67°
29
78°
63°
30
76°
68°
1
81°
62°
2
91°
69°
3
98°
70°
4
94°
72°
5
94°
70°
6
90°
72°
7
90°
71°
8
92°
70°
9
88°
72°
10
84°
69°
11
86°
71°
12
85°
70°
13
82°
69°
14
73°
61°
15
76°
63°
16
77°
65°
17
76°
65°
18
77°
64°
19
77°
65°
20
76°
65°
21
76°
64°
22
72°
64°
23
69°
63°
24
73°
62°
25
75°
62°
26
76°
63°
27
76°
62°
28
75°
63°
29
74°
62°
30
72°
62°
31
76°
63°
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 69° to 98°, with overnight lows between 61° and 72°. The average high for October is 81° 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 October weather will actually feel in Costa Mesa. See also: November | December | January.
