S
M
T
W
T
F
S
29
44°
33°
30
44°
33°
1
45°
40°
2
49°
42°
3
49°
39°
4
47°
37°
5
48°
34°
6
50°
34°
7
48°
36°
8
49°
40°
9
50°
39°
10
49°
34°
11
49°
32°
12
48°
33°
13
50°
39°
14
47°
38°
15
51°
36°
16
49°
41°
17
50°
42°
18
51°
40°
19
52°
39°
20
49°
40°
21
48°
41°
22
49°
40°
23
50°
37°
24
48°
33°
25
46°
30°
26
47°
30°
27
41°
29°
28
40°
32°
29
42°
29°
30
42°
33°
31
43°
41°
1
48°
36°
2
49°
32°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Seattle
Seattle's December 2026 forecast shows daily high temperatures ranging from 40° to 52°, with overnight lows between 29° and 42°. The average high for December is 47° with an average low of 36°. 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 Seattle. See also: January | February | March.
