S
M
T
W
T
F
S
26
103°
71°
27
93°
73°
28
95°
68°
29
92°
67°
30
96°
65°
31
90°
62°
1
94°
70°
2
102°
73°
3
100°
62°
4
80°
61°
5
92°
64°
6
96°
63°
7
95°
62°
8
95°
61°
9
94°
62°
10
91°
60°
11
91°
61°
12
90°
61°
13
87°
59°
14
88°
55°
15
89°
58°
16
90°
59°
17
89°
57°
18
89°
58°
19
87°
56°
20
85°
56°
21
87°
55°
22
86°
54°
23
86°
55°
24
88°
58°
25
89°
54°
26
85°
55°
27
88°
57°
28
89°
58°
29
88°
57°
30
89°
58°
31
89°
58°
1
88°
57°
2
88°
57°
3
87°
56°
4
85°
56°
5
83°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Mission Viejo
Mission Viejo's August 2026 forecast shows daily high temperatures ranging from 80° to 102°, with overnight lows between 54° and 73°. The average high for August is 89° with an average low of 59°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Mission Viejo. See also: September | October | November.
