S
M
T
W
T
F
S
26
85°
70°
27
86°
70°
28
89°
69°
29
90°
70°
30
89°
69°
31
89°
69°
1
88°
68°
2
89°
69°
3
89°
70°
4
88°
70°
5
90°
69°
6
89°
70°
7
88°
63°
8
90°
66°
9
90°
65°
10
85°
63°
11
84°
62°
12
85°
63°
13
89°
66°
14
89°
68°
15
88°
68°
16
84°
67°
17
84°
63°
18
85°
67°
19
89°
67°
20
83°
66°
21
86°
67°
22
84°
64°
23
84°
60°
24
87°
62°
25
89°
66°
26
89°
66°
27
88°
65°
28
84°
64°
29
84°
63°
30
85°
64°
31
87°
65°
1
82°
60°
2
81°
59°
3
81°
59°
4
80°
57°
5
80°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Ottawa
Ottawa's August 2026 forecast shows daily high temperatures ranging from 80° to 90°, with overnight lows between 57° and 70°. The average high for August is 86° with an average low of 65°. 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 Ottawa. See also: September | October | November.
