S
M
T
W
T
F
S
26
83°
66°
27
82°
67°
28
87°
68°
29
87°
68°
30
84°
67°
31
84°
68°
1
85°
68°
2
86°
69°
3
87°
68°
4
86°
67°
5
83°
67°
6
85°
68°
7
87°
65°
8
79°
61°
9
79°
60°
10
78°
62°
11
78°
67°
12
80°
67°
13
84°
68°
14
84°
67°
15
85°
65°
16
78°
63°
17
78°
58°
18
79°
59°
19
80°
65°
20
84°
64°
21
85°
65°
22
84°
64°
23
82°
58°
24
77°
57°
25
77°
57°
26
78°
58°
27
77°
57°
28
77°
56°
29
78°
56°
30
82°
58°
31
83°
63°
1
83°
63°
2
81°
57°
3
81°
53°
4
75°
53°
5
74°
57°
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 74° to 87°, with overnight lows between 53° and 69°. The average high for August is 82° with an average low of 63°. 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.
