S
M
T
W
T
F
S
26
82°
65°
27
82°
65°
28
80°
64°
29
81°
64°
30
80°
63°
31
74°
63°
1
74°
62°
2
75°
63°
3
74°
63°
4
75°
62°
5
75°
61°
6
74°
58°
7
74°
60°
8
75°
61°
9
77°
63°
10
74°
63°
11
76°
62°
12
76°
63°
13
77°
63°
14
77°
62°
15
74°
61°
16
73°
59°
17
73°
60°
18
74°
60°
19
74°
62°
20
77°
61°
21
74°
54°
22
71°
52°
23
71°
52°
24
72°
59°
25
73°
60°
26
78°
56°
27
74°
59°
28
73°
62°
29
81°
60°
30
83°
52°
31
73°
52°
1
73°
60°
2
78°
59°
3
72°
52°
4
75°
59°
5
80°
51°
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 71° to 83°, with overnight lows between 51° and 65°. The average high for August is 76° with an average low of 60°. 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.
