S
M
T
W
T
F
S
26
67°
41°
27
69°
44°
28
61°
48°
29
52°
41°
30
55°
37°
1
48°
35°
2
52°
30°
3
64°
37°
4
77°
46°
5
63°
45°
6
56°
37°
7
56°
35°
8
65°
33°
9
68°
47°
10
61°
33°
11
60°
36°
12
65°
32°
13
54°
43°
14
67°
40°
15
68°
54°
16
75°
53°
17
77°
62°
18
82°
63°
19
71°
47°
20
60°
41°
21
62°
47°
22
65°
47°
23
66°
48°
24
66°
50°
25
72°
53°
26
71°
49°
27
66°
55°
28
72°
56°
29
74°
55°
30
67°
50°
31
65°
47°
1
66°
46°
2
66°
47°
3
67°
49°
4
68°
57°
5
77°
59°
6
78°
60°
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 60° to 82°, with overnight lows between 40° and 63°. The average high for May is 70° with an average low of 51°. 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.
