S
M
T
W
T
F
S
29
52°
38°
30
53°
41°
1
52°
39°
2
57°
42°
3
57°
41°
4
56°
38°
5
52°
36°
6
52°
40°
7
53°
43°
8
52°
40°
9
52°
37°
10
51°
38°
11
50°
38°
12
50°
35°
13
51°
36°
14
50°
36°
15
51°
41°
16
50°
44°
17
54°
44°
18
55°
38°
19
54°
36°
20
51°
35°
21
50°
37°
22
51°
36°
23
52°
40°
24
53°
40°
25
51°
39°
26
52°
40°
27
53°
36°
28
52°
37°
29
54°
37°
30
57°
38°
31
57°
40°
1
56°
38°
2
57°
39°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Arcata
Arcata's December 2026 forecast shows daily high temperatures ranging from 50° to 57°, with overnight lows between 35° and 44°. The average high for December is 53° with an average low of 39°. 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 Arcata. See also: January | February | March.