S
M
T
W
T
F
S
26
85°
70°
27
84°
72°
28
87°
72°
29
86°
71°
30
85°
72°
31
89°
74°
1
89°
73°
2
85°
72°
3
84°
70°
4
84°
70°
5
85°
73°
6
85°
73°
7
86°
72°
8
89°
73°
9
86°
72°
10
86°
73°
11
84°
72°
12
83°
71°
13
84°
72°
14
87°
73°
15
88°
72°
16
87°
72°
17
83°
71°
18
85°
72°
19
83°
72°
20
87°
71°
21
86°
72°
22
83°
72°
23
85°
71°
24
82°
72°
25
84°
72°
26
83°
71°
27
83°
72°
28
82°
71°
29
86°
70°
30
87°
71°
31
85°
69°
1
85°
69°
2
84°
68°
3
84°
69°
4
83°
67°
5
84°
66°
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 82° to 89°, with overnight lows between 66° and 74°. The average high for August is 85° with an average low of 71°. 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.
