S
M
T
W
T
F
S
26
60°
34°
27
65°
34°
28
52°
40°
29
48°
42°
30
47°
43°
1
62°
38°
2
51°
37°
3
55°
40°
4
71°
39°
5
68°
47°
6
59°
51°
7
63°
43°
8
59°
36°
9
56°
36°
10
61°
47°
11
61°
42°
12
59°
37°
13
52°
36°
14
61°
47°
15
60°
48°
16
75°
49°
17
84°
61°
18
64°
51°
19
82°
65°
20
86°
50°
21
61°
45°
22
60°
51°
23
55°
49°
24
54°
48°
25
59°
50°
26
63°
52°
27
64°
51°
28
67°
53°
29
69°
54°
30
72°
55°
31
74°
56°
1
70°
52°
2
64°
51°
3
64°
52°
4
65°
54°
5
65°
55°
6
72°
56°
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 54° to 86°, with overnight lows between 45° and 65°. The average high for May is 67° with an average low of 53°. 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.
