S
M
T
W
T
F
S
26
84°
69°
27
84°
68°
28
85°
69°
29
84°
69°
30
85°
68°
31
81°
65°
1
80°
61°
2
80°
63°
3
81°
66°
4
81°
65°
5
83°
67°
6
86°
68°
7
87°
69°
8
86°
68°
9
87°
67°
10
86°
67°
11
87°
66°
12
88°
68°
13
87°
69°
14
89°
59°
15
81°
62°
16
81°
60°
17
80°
58°
18
85°
60°
19
84°
58°
20
80°
57°
21
79°
58°
22
79°
59°
23
80°
57°
24
80°
61°
25
82°
64°
26
80°
65°
27
86°
59°
28
87°
57°
29
78°
57°
30
77°
58°
31
77°
57°
1
78°
55°
2
76°
56°
3
77°
55°
4
77°
56°
5
78°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Onalaska
Onalaska's August 2026 forecast shows daily high temperatures ranging from 76° to 89°, with overnight lows between 55° and 69°. The average high for August is 82° with an average low of 62°. 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 Onalaska. See also: September | October | November.
