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