S
M
T
W
T
F
S
26
60°
34°
27
65°
34°
28
52°
40°
29
48°
42°
30
48°
46°
1
60°
39°
2
52°
45°
3
50°
40°
4
57°
48°
5
66°
51°
6
63°
52°
7
58°
47°
8
59°
42°
9
57°
43°
10
59°
44°
11
56°
44°
12
59°
45°
13
61°
44°
14
58°
45°
15
62°
47°
16
60°
45°
17
59°
42°
18
60°
50°
19
59°
50°
20
63°
49°
21
65°
51°
22
68°
48°
23
60°
49°
24
60°
50°
25
63°
48°
26
64°
47°
27
62°
47°
28
61°
49°
29
62°
51°
30
64°
52°
31
63°
50°
1
64°
47°
2
63°
47°
3
64°
48°
4
63°
48°
5
64°
49°
6
64°
51°
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 48° to 68°, with overnight lows between 39° and 52°. The average high for May is 61° with an average low of 47°. 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.
