S
M
T
W
T
F
S
29
45°
27°
30
36°
25°
1
37°
27°
2
39°
24°
3
38°
27°
4
43°
26°
5
39°
25°
6
40°
21°
7
33°
20°
8
34°
24°
9
35°
20°
10
31°
19°
11
34°
25°
12
41°
25°
13
41°
24°
14
39°
23°
15
38°
23°
16
37°
24°
17
41°
23°
18
28°
5°
19
25°
6°
20
26°
11°
21
30°
17°
22
36°
10°
23
35°
15°
24
28°
10°
25
35°
4°
26
25°
16°
27
30°
20°
28
40°
18°
29
38°
8°
30
36°
4°
31
27°
8°
1
24°
1°
2
29°
-2°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Cornish
Cornish's December 2026 forecast shows daily high temperatures ranging from 24° to 45°, with overnight lows between -2° and 27°. The average high for December is 35° with an average low of 17°. 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 Cornish. See also: January | February | March.