S
M
T
W
T
F
S
26
74°
59°
27
79°
59°
28
73°
58°
29
75°
56°
30
79°
54°
31
84°
56°
1
72°
58°
2
71°
56°
3
76°
53°
4
81°
58°
5
87°
59°
6
88°
59°
7
86°
59°
8
83°
58°
9
77°
55°
10
74°
55°
11
79°
55°
12
79°
58°
13
81°
56°
14
78°
56°
15
75°
57°
16
75°
58°
17
80°
54°
18
80°
57°
19
83°
55°
20
86°
59°
21
81°
60°
22
73°
60°
23
73°
58°
24
77°
58°
25
82°
57°
26
73°
56°
27
72°
55°
28
73°
55°
29
71°
56°
30
70°
55°
31
72°
55°
1
71°
56°
2
72°
57°
3
75°
56°
4
74°
57°
5
74°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Seattle
Seattle's August 2026 forecast shows daily high temperatures ranging from 70° to 82°, with overnight lows between 55° and 60°. The average high for August is 73° with an average low of 57°. 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 Seattle. See also: September | October | November.