S
M
T
W
T
F
S
29
67°
47°
30
63°
43°
1
64°
44°
2
64°
46°
3
62°
44°
4
63°
46°
5
64°
43°
6
67°
44°
7
69°
46°
8
66°
46°
9
61°
42°
10
61°
46°
11
61°
36°
12
60°
36°
13
62°
41°
14
66°
40°
15
67°
42°
16
66°
38°
17
62°
45°
18
64°
44°
19
65°
47°
20
65°
47°
21
68°
37°
22
66°
35°
23
60°
35°
24
59°
37°
25
60°
40°
26
62°
42°
27
63°
41°
28
60°
39°
29
60°
38°
30
59°
36°
31
59°
35°
1
60°
37°
2
60°
38°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Rialto
Rialto's December 2026 forecast shows daily high temperatures ranging from 59° to 69°, with overnight lows between 35° and 47°. The average high for December is 63° with an average low of 41°. 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 Rialto. See also: January | February | March.
