S
M
T
W
T
F
S
29
40°
29°
30
39°
30°
1
40°
35°
2
43°
39°
3
45°
37°
4
44°
37°
5
43°
32°
6
44°
30°
7
44°
32°
8
46°
37°
9
45°
36°
10
45°
32°
11
44°
30°
12
45°
29°
13
46°
38°
14
42°
33°
15
44°
31°
16
42°
38°
17
43°
39°
18
45°
38°
19
46°
36°
20
44°
37°
21
43°
38°
22
44°
36°
23
45°
34°
24
43°
29°
25
41°
23°
26
42°
24°
27
34°
24°
28
33°
27°
29
36°
23°
30
37°
28°
31
36°
36°
1
43°
32°
2
43°
26°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Sumas
Sumas's December 2026 forecast shows daily high temperatures ranging from 33° to 46°, with overnight lows between 23° and 39°. The average high for December is 42° with an average low of 32°. 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 Sumas. See also: January | February | March.
