S
M
T
W
T
F
S
26
84°
62°
27
81°
56°
28
82°
60°
29
83°
60°
30
84°
52°
31
79°
52°
1
78°
60°
2
83°
58°
3
84°
56°
4
83°
54°
5
82°
54°
6
80°
60°
7
82°
61°
8
83°
59°
9
84°
56°
10
84°
52°
11
82°
51°
12
76°
51°
13
79°
50°
14
78°
50°
15
78°
53°
16
81°
58°
17
82°
61°
18
83°
62°
19
82°
61°
20
84°
61°
21
82°
59°
22
80°
55°
23
79°
58°
24
80°
55°
25
72°
54°
26
72°
52°
27
71°
50°
28
69°
48°
29
71°
47°
30
72°
49°
31
72°
50°
1
71°
57°
2
70°
57°
3
69°
56°
4
69°
54°
5
68°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Issaquah
Issaquah's August 2026 forecast shows daily high temperatures ranging from 68° to 84°, with overnight lows between 47° and 62°. The average high for August is 78° with an average low of 55°. 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 Issaquah. See also: September | October | November.
