S
M
T
W
T
F
S
26
84°
70°
27
92°
69°
28
82°
58°
29
82°
55°
30
86°
64°
31
78°
68°
1
75°
64°
2
79°
58°
3
81°
60°
4
81°
62°
5
79°
63°
6
82°
64°
7
83°
63°
8
85°
65°
9
84°
66°
10
83°
64°
11
83°
65°
12
81°
63°
13
82°
65°
14
78°
60°
15
76°
59°
16
77°
66°
17
84°
66°
18
78°
63°
19
77°
61°
20
77°
65°
21
81°
59°
22
75°
58°
23
75°
58°
24
76°
58°
25
76°
57°
26
75°
56°
27
76°
59°
28
78°
59°
29
81°
64°
30
81°
64°
31
75°
65°
1
80°
63°
2
78°
59°
3
75°
56°
4
77°
60°
5
80°
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 75° to 86°, with overnight lows between 56° and 68°. The average high for August is 79° 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.
