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