S
M
T
W
T
F
S
26
93°
72°
27
97°
73°
28
85°
66°
29
88°
67°
30
88°
68°
31
75°
63°
1
85°
63°
2
84°
65°
3
85°
63°
4
78°
66°
5
77°
59°
6
81°
57°
7
82°
66°
8
82°
60°
9
81°
64°
10
87°
66°
11
87°
69°
12
87°
68°
13
80°
66°
14
81°
63°
15
83°
71°
16
83°
60°
17
82°
65°
18
83°
62°
19
79°
57°
20
81°
61°
21
80°
62°
22
81°
60°
23
80°
61°
24
84°
66°
25
84°
64°
26
81°
62°
27
80°
61°
28
77°
68°
29
81°
65°
30
85°
66°
31
74°
61°
1
74°
62°
2
75°
59°
3
74°
56°
4
75°
61°
5
78°
59°
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 74° to 85°, with overnight lows between 56° and 71°. The average high for August is 80° 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.
