S
M
T
W
T
F
S
26
93°
68°
27
95°
67°
28
92°
65°
29
92°
66°
30
93°
64°
31
99°
64°
1
98°
66°
2
97°
66°
3
94°
65°
4
90°
64°
5
90°
64°
6
92°
65°
7
94°
67°
8
99°
67°
9
96°
69°
10
94°
69°
11
94°
69°
12
89°
66°
13
83°
65°
14
85°
64°
15
88°
64°
16
91°
64°
17
94°
64°
18
96°
67°
19
100°
66°
20
96°
67°
21
99°
71°
22
98°
69°
23
102°
71°
24
102°
70°
25
100°
70°
26
102°
71°
27
98°
76°
28
100°
73°
29
97°
73°
30
92°
70°
31
90°
63°
1
88°
61°
2
87°
61°
3
86°
64°
4
85°
63°
5
84°
65°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Diamond Bar
Diamond Bar's August 2026 forecast shows daily high temperatures ranging from 84° to 90°, with overnight lows between 61° and 65°. The average high for August is 87° 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 Diamond Bar. See also: September | October | November.
