S
M
T
W
T
F
S
28
70°
63°
29
71°
64°
30
70°
63°
1
71°
63°
2
73°
64°
3
71°
62°
4
72°
62°
5
72°
64°
6
71°
64°
7
72°
64°
8
71°
63°
9
71°
64°
10
71°
64°
11
74°
66°
12
77°
66°
13
80°
68°
14
80°
69°
15
83°
71°
16
77°
70°
17
73°
69°
18
76°
70°
19
77°
68°
20
73°
69°
21
75°
68°
22
76°
69°
23
79°
70°
24
73°
64°
25
73°
66°
26
76°
68°
27
76°
68°
28
76°
68°
29
75°
67°
30
73°
65°
31
71°
65°
1
74°
67°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
July Weather in Costa Mesa
Costa Mesa's July 2026 forecast shows daily high temperatures ranging from 71° to 83°, with overnight lows between 64° and 71°. The average high for July is 76° 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 July weather will actually feel in Costa Mesa. See also: August | September | October.
