S
M
T
W
T
F
S
29
43°
31°
30
38°
28°
1
38°
28°
2
37°
31°
3
43°
31°
4
43°
30°
5
42°
30°
6
40°
32°
7
38°
32°
8
40°
31°
9
40°
30°
10
37°
28°
11
45°
27°
12
45°
29°
13
37°
29°
14
44°
26°
15
43°
20°
16
38°
18°
17
32°
26°
18
35°
24°
19
40°
20°
20
36°
26°
21
34°
27°
22
41°
27°
23
42°
28°
24
42°
30°
25
44°
21°
26
44°
19°
27
43°
17°
28
28°
19°
29
28°
25°
30
37°
25°
31
40°
26°
1
40°
27°
2
42°
26°
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 28° to 45°, with overnight lows between 17° and 32°. The average high for December is 39° with an average low of 26°. 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.
