S
M
T
W
T
F
S
26
64°
34°
27
70°
37°
28
63°
46°
29
68°
45°
30
70°
50°
1
68°
48°
2
66°
48°
3
61°
48°
4
64°
52°
5
61°
50°
6
59°
41°
7
59°
50°
8
63°
49°
9
65°
50°
10
61°
41°
11
60°
47°
12
59°
50°
13
59°
45°
14
56°
42°
15
57°
46°
16
57°
46°
17
59°
47°
18
58°
46°
19
60°
47°
20
56°
44°
21
58°
48°
22
57°
47°
23
57°
48°
24
59°
50°
25
62°
50°
26
64°
49°
27
64°
51°
28
59°
49°
29
61°
45°
30
63°
51°
31
64°
52°
1
65°
52°
2
64°
51°
3
65°
51°
4
61°
52°
5
62°
52°
6
65°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Portsmouth
Portsmouth's May 2026 forecast shows daily high temperatures ranging from 56° to 65°, with overnight lows between 41° and 52°. The average high for May is 61° with an average low of 48°. 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 Portsmouth. See also: June | July | August.
