S
M
T
W
T
F
S
26
80°
51°
27
85°
55°
28
80°
61°
29
70°
56°
30
64°
46°
1
64°
43°
2
62°
40°
3
67°
37°
4
81°
57°
5
69°
59°
6
63°
49°
7
61°
42°
8
69°
49°
9
73°
57°
10
75°
61°
11
71°
54°
12
74°
56°
13
73°
60°
14
76°
57°
15
74°
56°
16
77°
60°
17
79°
56°
18
78°
62°
19
79°
61°
20
77°
61°
21
77°
56°
22
73°
54°
23
72°
53°
24
73°
55°
25
73°
56°
26
74°
54°
27
73°
55°
28
75°
56°
29
76°
58°
30
79°
64°
31
80°
65°
1
77°
64°
2
78°
61°
3
78°
60°
4
79°
62°
5
80°
66°
6
84°
66°
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 61° to 84°, with overnight lows between 42° and 66°. The average high for May is 75° with an average low of 58°. 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.
