S
M
T
W
T
F
S
29
48°
37°
30
54°
33°
1
50°
33°
2
41°
35°
3
46°
35°
4
47°
37°
5
49°
42°
6
52°
43°
7
52°
46°
8
55°
42°
9
56°
41°
10
53°
40°
11
50°
33°
12
47°
34°
13
40°
33°
14
43°
33°
15
40°
29°
16
39°
27°
17
38°
27°
18
36°
28°
19
37°
27°
20
37°
30°
21
40°
37°
22
44°
38°
23
50°
34°
24
49°
30°
25
43°
23°
26
39°
22°
27
36°
32°
28
36°
25°
29
43°
22°
30
35°
21°
31
31°
25°
1
33°
32°
2
39°
24°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Sunnyside
Sunnyside's December 2026 forecast shows daily high temperatures ranging from 31° to 56°, with overnight lows between 21° and 46°. The average high for December is 44° with an average low of 32°. 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 Sunnyside. See also: January | February | March.
