S
M
T
W
T
F
S
30
38°
21°
1
30°
20°
2
29°
19°
3
28°
18°
4
29°
17°
5
33°
16°
6
35°
26°
7
36°
29°
8
31°
20°
9
43°
20°
10
43°
29°
11
30°
28°
12
32°
28°
13
30°
7°
14
7°
-4°
15
26°
-4°
16
40°
19°
17
48°
37°
18
55°
39°
19
40°
21°
20
52°
23°
21
41°
22°
22
48°
8°
23
60°
43°
24
53°
35°
25
54°
46°
26
65°
45°
27
52°
45°
28
67°
33°
29
33°
14°
30
28°
14°
31
35°
28°
1
35°
21°
2
31°
19°
3
34°
24°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Waterloo
Waterloo's December 2025 forecast shows daily high temperatures ranging from ° to °, with overnight lows between ° and °. The average high for December is ° with an average low of °. 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 Waterloo. See also: January | February | March.
