S
M
T
W
T
F
S
29
42°
23°
30
41°
23°
1
42°
24°
2
43°
28°
3
45°
28°
4
50°
31°
5
50°
35°
6
47°
33°
7
46°
31°
8
40°
29°
9
41°
23°
10
40°
22°
11
54°
34°
12
54°
27°
13
56°
24°
14
45°
21°
15
39°
23°
16
41°
20°
17
39°
25°
18
43°
32°
19
45°
34°
20
52°
34°
21
53°
33°
22
53°
33°
23
51°
35°
24
55°
31°
25
55°
23°
26
54°
20°
27
37°
23°
28
43°
30°
29
50°
32°
30
50°
34°
31
52°
35°
1
53°
30°
2
55°
23°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Portland
Portland's December 2026 forecast shows daily high temperatures ranging from 37° to 56°, with overnight lows between 20° and 35°. The average high for December is 47° with an average low of 28°. 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 Portland. See also: January | February | March.
