S
M
T
W
T
F
S
26
61°
41°
27
70°
35°
28
62°
38°
29
61°
48°
30
59°
46°
1
63°
35°
2
57°
43°
3
60°
40°
4
72°
35°
5
82°
53°
6
66°
51°
7
63°
45°
8
61°
38°
9
58°
49°
10
70°
48°
11
62°
46°
12
67°
34°
13
68°
47°
14
61°
49°
15
65°
48°
16
79°
42°
17
86°
55°
18
96°
65°
19
97°
68°
20
91°
52°
21
71°
45°
22
66°
50°
23
55°
49°
24
65°
52°
25
74°
53°
26
75°
54°
27
74°
53°
28
76°
53°
29
78°
52°
30
76°
53°
31
80°
51°
1
75°
54°
2
72°
53°
3
69°
54°
4
70°
56°
5
74°
54°
6
74°
55°
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 55° to 97°, with overnight lows between 45° and 68°. The average high for May is 75° 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.
