S
M
T
W
T
F
S
26
35°
30°
27
36°
26°
28
58°
25°
29
58°
29°
30
57°
29°
1
53°
33°
2
50°
38°
3
58°
41°
4
45°
40°
5
63°
39°
6
69°
45°
7
63°
47°
8
54°
41°
9
55°
35°
10
62°
35°
11
59°
38°
12
51°
40°
13
49°
39°
14
66°
38°
15
52°
37°
16
47°
36°
17
69°
38°
18
51°
39°
19
53°
34°
20
54°
34°
21
57°
35°
22
51°
33°
23
53°
34°
24
60°
37°
25
59°
35°
26
47°
32°
27
48°
31°
28
44°
35°
29
44°
36°
30
47°
33°
31
49°
36°
1
51°
37°
2
53°
41°
3
61°
41°
4
65°
44°
5
64°
45°
6
65°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Portland
Portland's May 2026 forecast shows daily high temperatures ranging from 44° to 65°, with overnight lows between 31° and 47°. The average high for May is 54° with an average low of 38°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how May weather will actually feel in Portland. See also: June | July | August.
