S
M
T
W
T
F
S
29
71°
51°
30
70°
49°
1
71°
40°
2
56°
37°
3
57°
37°
4
59°
49°
5
66°
41°
6
57°
37°
7
57°
38°
8
55°
36°
9
54°
36°
10
55°
35°
11
56°
36°
12
58°
38°
13
64°
44°
14
59°
39°
15
58°
38°
16
56°
40°
17
59°
37°
18
56°
35°
19
55°
33°
20
55°
34°
21
56°
36°
22
60°
35°
23
54°
34°
24
53°
34°
25
54°
33°
26
54°
34°
27
56°
34°
28
56°
35°
29
55°
35°
30
53°
36°
31
55°
33°
1
54°
32°
2
54°
38°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Onalaska
Onalaska's December 2026 forecast shows daily high temperatures ranging from 53° to 71°, with overnight lows between 32° and 51°. The average high for December is 58° with an average low of 37°. 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 Onalaska. See also: January | February | March.
