S
M
T
W
T
F
S
26
76°
52°
27
80°
51°
28
81°
60°
29
72°
63°
30
78°
63°
31
83°
63°
1
84°
65°
2
87°
70°
3
76°
62°
4
87°
60°
5
83°
67°
6
88°
72°
7
91°
70°
8
82°
66°
9
87°
65°
10
89°
64°
11
85°
65°
12
82°
63°
13
79°
59°
14
76°
60°
15
76°
59°
16
78°
57°
17
76°
61°
18
75°
59°
19
75°
61°
20
76°
59°
21
75°
56°
22
75°
61°
23
81°
62°
24
78°
62°
25
76°
61°
26
74°
59°
27
74°
60°
28
73°
62°
29
76°
60°
30
78°
61°
31
78°
60°
1
79°
56°
2
71°
56°
3
71°
55°
4
72°
53°
5
71°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Portsmouth
Portsmouth's August 2026 forecast shows daily high temperatures ranging from 71° to 91°, with overnight lows between 53° and 72°. The average high for August is 78° with an average low of 61°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Portsmouth. See also: September | October | November.
