S
M
T
W
T
F
S
26
62°
41°
27
72°
37°
28
71°
40°
29
68°
45°
30
58°
48°
1
64°
41°
2
56°
47°
3
56°
40°
4
70°
51°
5
77°
56°
6
66°
53°
7
65°
40°
8
63°
43°
9
59°
47°
10
67°
52°
11
64°
47°
12
65°
44°
13
66°
50°
14
67°
51°
15
65°
50°
16
69°
51°
17
71°
49°
18
75°
54°
19
74°
53°
20
73°
54°
21
72°
53°
22
72°
50°
23
68°
47°
24
66°
49°
25
68°
48°
26
68°
52°
27
69°
48°
28
69°
49°
29
70°
50°
30
69°
49°
31
70°
57°
1
74°
55°
2
72°
51°
3
71°
55°
4
76°
58°
5
74°
56°
6
73°
58°
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 59° to 77°, with overnight lows between 40° and 58°. The average high for May is 69° with an average low of 51°. 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.
