S
M
T
W
T
F
S
26
59°
42°
27
72°
38°
28
65°
56°
29
58°
40°
30
47°
39°
1
44°
33°
2
46°
34°
3
57°
34°
4
73°
49°
5
68°
49°
6
53°
42°
7
54°
36°
8
56°
40°
9
68°
47°
10
54°
40°
11
54°
35°
12
61°
31°
13
63°
45°
14
48°
43°
15
61°
41°
16
71°
54°
17
71°
64°
18
75°
68°
19
74°
66°
20
71°
46°
21
60°
45°
22
67°
42°
23
61°
50°
24
69°
54°
25
65°
49°
26
66°
46°
27
69°
51°
28
66°
46°
29
68°
46°
30
64°
47°
31
68°
53°
1
68°
49°
2
70°
51°
3
73°
56°
4
76°
62°
5
78°
64°
6
74°
62°
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 64° to 78°, with overnight lows between 46° and 64°. The average high for May is 71° with an average low of 54°. 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.
