S
M
T
W
T
F
S
26
57°
41°
27
66°
40°
28
64°
41°
29
62°
44°
30
54°
46°
1
63°
46°
2
53°
46°
3
54°
43°
4
65°
51°
5
64°
54°
6
62°
55°
7
63°
46°
8
60°
45°
9
59°
45°
10
61°
47°
11
62°
46°
12
61°
47°
13
59°
48°
14
61°
47°
15
61°
47°
16
66°
49°
17
65°
48°
18
69°
53°
19
68°
52°
20
64°
52°
21
64°
53°
22
65°
53°
23
65°
50°
24
61°
49°
25
63°
49°
26
64°
55°
27
64°
52°
28
65°
50°
29
64°
49°
30
65°
52°
31
66°
56°
1
69°
55°
2
68°
52°
3
67°
56°
4
70°
57°
5
67°
56°
6
67°
57°
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 59° to 70°, with overnight lows between 45° and 57°. The average high for May is 64° 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 Portsmouth. See also: June | July | August.
