S
M
T
W
T
F
S
26
85°
66°
27
81°
60°
28
79°
62°
29
82°
66°
30
81°
62°
31
81°
59°
1
82°
60°
2
80°
59°
3
80°
60°
4
81°
59°
5
80°
59°
6
80°
61°
7
81°
61°
8
80°
66°
9
81°
66°
10
83°
64°
11
82°
66°
12
84°
65°
13
84°
60°
14
87°
58°
15
79°
58°
16
79°
59°
17
80°
60°
18
80°
58°
19
78°
57°
20
78°
57°
21
79°
58°
22
78°
60°
23
78°
58°
24
79°
57°
25
78°
63°
26
81°
65°
27
84°
65°
28
85°
64°
29
86°
56°
30
84°
58°
31
77°
57°
1
77°
59°
2
78°
62°
3
83°
54°
4
79°
56°
5
76°
61°
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 76° to 87°, with overnight lows between 54° and 66°. The average high for August is 81° with an average low of 61°. 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.
