S
M
T
W
T
F
S
27
78°
54°
28
79°
55°
29
81°
56°
30
81°
58°
1
80°
56°
2
83°
57°
3
86°
61°
4
86°
61°
5
85°
60°
6
85°
60°
7
82°
57°
8
82°
58°
9
83°
58°
10
83°
59°
11
84°
60°
12
80°
49°
13
77°
48°
14
77°
49°
15
76°
50°
16
77°
54°
17
78°
51°
18
77°
51°
19
77°
52°
20
80°
52°
21
77°
56°
22
79°
53°
23
82°
51°
24
80°
50°
25
78°
53°
26
76°
50°
27
76°
50°
28
77°
53°
29
77°
51°
30
76°
53°
31
79°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
October Weather in Diamond Bar
Diamond Bar's October 2026 forecast shows daily high temperatures ranging from 76° to 86°, with overnight lows between 48° and 61°. The average high for October is 80° with an average low of 54°. 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 Diamond Bar. See also: November | December | January.
