S
M
T
W
T
F
S
26
83°
65°
27
84°
72°
28
82°
67°
29
70°
61°
30
68°
57°
1
64°
50°
2
73°
46°
3
79°
54°
4
82°
62°
5
83°
67°
6
75°
53°
7
69°
48°
8
74°
55°
9
79°
60°
10
80°
61°
11
81°
63°
12
83°
62°
13
82°
58°
14
83°
61°
15
84°
66°
16
84°
66°
17
83°
65°
18
84°
66°
19
85°
67°
20
85°
67°
21
84°
66°
22
85°
67°
23
80°
67°
24
84°
66°
25
82°
68°
26
81°
67°
27
82°
62°
28
81°
63°
29
85°
67°
30
86°
66°
31
86°
68°
1
85°
68°
2
87°
69°
3
88°
70°
4
88°
69°
5
83°
65°
6
82°
64°
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 88°, with overnight lows between 46° and 70°. The average high for May is 82° with an average low of 63°. 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.
