S
M
T
W
T
F
S
29
44°
31°
30
43°
30°
1
44°
38°
2
49°
39°
3
48°
36°
4
48°
34°
5
49°
31°
6
50°
31°
7
46°
32°
8
45°
36°
9
49°
34°
10
46°
30°
11
46°
30°
12
45°
31°
13
49°
36°
14
43°
37°
15
51°
36°
16
47°
39°
17
45°
36°
18
46°
37°
19
48°
38°
20
46°
37°
21
44°
40°
22
47°
37°
23
46°
36°
24
44°
33°
25
46°
29°
26
45°
29°
27
39°
30°
28
38°
33°
29
39°
30°
30
39°
38°
31
45°
40°
1
47°
34°
2
46°
33°
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 38° to 51°, with overnight lows between 29° and 40°. The average high for December is 45° with an average low of 34°. 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.
