S
M
T
W
T
F
S
26
63°
43°
27
66°
42°
28
66°
47°
29
67°
50°
30
67°
51°
1
61°
50°
2
60°
51°
3
60°
50°
4
64°
47°
5
69°
52°
6
61°
50°
7
66°
52°
8
64°
48°
9
67°
49°
10
61°
47°
11
60°
46°
12
61°
45°
13
63°
46°
14
65°
48°
15
63°
48°
16
62°
47°
17
62°
46°
18
63°
46°
19
68°
48°
20
73°
54°
21
74°
55°
22
72°
52°
23
64°
46°
24
64°
46°
25
64°
47°
26
69°
47°
27
74°
54°
28
75°
57°
29
77°
58°
30
76°
56°
31
71°
49°
1
74°
50°
2
75°
56°
3
76°
57°
4
77°
48°
5
75°
56°
6
77°
49°
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 77°, with overnight lows between 42° and 58°. The average high for May is 68° with an average low of 50°. 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.
