S
M
T
W
T
F
S
26
85°
69°
27
90°
72°
28
91°
69°
29
85°
70°
30
86°
72°
31
88°
71°
1
90°
71°
2
84°
75°
3
89°
75°
4
88°
73°
5
89°
75°
6
91°
75°
7
92°
74°
8
93°
74°
9
94°
76°
10
93°
71°
11
89°
71°
12
87°
74°
13
90°
76°
14
87°
71°
15
88°
74°
16
85°
76°
17
91°
72°
18
88°
67°
19
90°
70°
20
90°
69°
21
87°
68°
22
88°
67°
23
89°
68°
24
89°
69°
25
86°
68°
26
86°
67°
27
85°
66°
28
84°
64°
29
82°
66°
30
87°
69°
31
88°
69°
1
88°
68°
2
87°
69°
3
88°
70°
4
88°
69°
5
85°
68°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in National Harbor
National Harbor's August 2026 forecast shows daily high temperatures ranging from 82° to 91°, with overnight lows between 64° and 76°. The average high for August is 87° with an average low of 69°. 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 National Harbor. See also: September | October | November.
