S
M
T
W
T
F
S
29
68°
47°
30
68°
46°
1
64°
47°
2
68°
48°
3
69°
47°
4
69°
49°
5
67°
46°
6
66°
46°
7
65°
45°
8
66°
45°
9
67°
46°
10
66°
44°
11
64°
43°
12
64°
46°
13
68°
47°
14
69°
46°
15
69°
47°
16
68°
45°
17
68°
44°
18
66°
41°
19
62°
40°
20
62°
40°
21
61°
41°
22
62°
41°
23
62°
40°
24
63°
40°
25
62°
39°
26
61°
39°
27
62°
38°
28
64°
42°
29
63°
43°
30
64°
45°
31
65°
44°
1
63°
40°
2
65°
42°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Rancho Bernardo
Rancho Bernardo's December 2026 forecast shows daily high temperatures ranging from 61° to 69°, with overnight lows between 38° and 49°. The average high for December is 65° with an average low of 44°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how December weather will actually feel in Rancho Bernardo. See also: January | February | March.
