S
M
T
W
T
F
S
26
89°
70°
27
88°
69°
28
89°
68°
29
86°
68°
30
88°
67°
31
82°
66°
1
81°
62°
2
82°
64°
3
80°
64°
4
81°
65°
5
83°
68°
6
89°
70°
7
91°
70°
8
89°
69°
9
89°
68°
10
88°
68°
11
89°
67°
12
88°
67°
13
89°
69°
14
90°
67°
15
86°
61°
16
81°
59°
17
82°
58°
18
81°
56°
19
82°
57°
20
80°
55°
21
79°
57°
22
80°
55°
23
84°
58°
24
85°
64°
25
88°
64°
26
90°
63°
27
88°
65°
28
90°
63°
29
90°
56°
30
80°
55°
31
78°
57°
1
78°
52°
2
77°
55°
3
79°
60°
4
86°
60°
5
85°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Fullerton
Fullerton's August 2026 forecast shows daily high temperatures ranging from 77° to 91°, with overnight lows between 52° and 70°. The average high for August is 85° 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 August weather will actually feel in Fullerton. See also: September | October | November.
