S
M
T
W
T
F
S
26
66°
47°
27
65°
48°
28
67°
47°
29
69°
48°
30
65°
50°
1
66°
49°
2
62°
49°
3
62°
49°
4
65°
50°
5
66°
49°
6
66°
43°
7
69°
44°
8
68°
50°
9
62°
51°
10
65°
49°
11
65°
48°
12
62°
45°
13
62°
45°
14
63°
46°
15
67°
50°
16
70°
54°
17
65°
54°
18
65°
53°
19
66°
54°
20
72°
52°
21
71°
51°
22
67°
50°
23
64°
47°
24
64°
48°
25
69°
51°
26
73°
54°
27
70°
52°
28
74°
54°
29
74°
54°
30
66°
50°
31
65°
47°
1
65°
48°
2
66°
48°
3
74°
54°
4
73°
56°
5
67°
49°
6
73°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Downtown Portland
Downtown Portland's May 2026 forecast shows daily high temperatures ranging from 62° to 74°, with overnight lows between 43° and 56°. The average high for May is 67° with an average low of 50°. 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 Downtown Portland. See also: June | July | August.
