S
M
T
W
T
F
S
26
86°
65°
27
85°
65°
28
84°
64°
29
81°
60°
30
80°
58°
31
77°
57°
1
77°
57°
2
78°
58°
3
79°
64°
4
79°
60°
5
80°
62°
6
82°
65°
7
83°
63°
8
79°
61°
9
80°
58°
10
80°
58°
11
81°
60°
12
84°
63°
13
85°
64°
14
86°
65°
15
84°
64°
16
86°
65°
17
87°
63°
18
80°
57°
19
79°
56°
20
77°
55°
21
78°
55°
22
79°
56°
23
79°
56°
24
81°
57°
25
83°
56°
26
84°
59°
27
85°
58°
28
82°
56°
29
77°
55°
30
78°
55°
31
80°
59°
1
83°
53°
2
78°
54°
3
77°
55°
4
79°
60°
5
82°
61°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Ontario
Ontario's August 2026 forecast shows daily high temperatures ranging from 77° to 87°, with overnight lows between 53° and 65°. The average high for August is 81° with an average low of 59°. 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 Ontario. See also: September | October | November.
