S
M
T
W
T
F
S
26
86°
69°
27
86°
69°
28
87°
68°
29
86°
68°
30
85°
66°
31
80°
62°
1
79°
66°
2
78°
67°
3
78°
64°
4
83°
68°
5
85°
68°
6
85°
67°
7
81°
63°
8
78°
63°
9
78°
65°
10
81°
64°
11
82°
66°
12
83°
67°
13
85°
68°
14
86°
67°
15
85°
68°
16
87°
62°
17
86°
59°
18
78°
57°
19
76°
56°
20
76°
56°
21
77°
57°
22
78°
57°
23
78°
58°
24
79°
58°
25
81°
62°
26
83°
60°
27
82°
57°
28
77°
56°
29
78°
60°
30
82°
63°
31
82°
56°
1
83°
56°
2
77°
55°
3
76°
60°
4
78°
64°
5
83°
55°
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 55° and 69°. The average high for August is 81° with an average low of 62°. 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.
