S
M
T
W
T
F
S
26
83°
63°
27
83°
66°
28
82°
66°
29
79°
62°
30
87°
61°
31
88°
70°
1
77°
67°
2
77°
62°
3
81°
59°
4
84°
63°
5
84°
65°
6
84°
64°
7
86°
63°
8
88°
65°
9
84°
63°
10
84°
61°
11
85°
66°
12
83°
62°
13
83°
66°
14
78°
59°
15
76°
58°
16
77°
61°
17
79°
64°
18
77°
59°
19
77°
59°
20
78°
61°
21
79°
58°
22
76°
57°
23
75°
56°
24
75°
57°
25
76°
56°
26
76°
57°
27
75°
56°
28
77°
59°
29
78°
60°
30
81°
63°
31
75°
64°
1
75°
63°
2
78°
59°
3
75°
54°
4
74°
55°
5
74°
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 74° to 88°, with overnight lows between 54° and 70°. The average high for August is 79° 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.
