S
M
T
W
T
F
S
26
84°
70°
27
92°
69°
28
82°
58°
29
82°
55°
30
81°
58°
31
73°
65°
1
67°
63°
2
76°
59°
3
81°
60°
4
83°
66°
5
81°
67°
6
80°
65°
7
84°
66°
8
81°
64°
9
85°
66°
10
88°
73°
11
79°
68°
12
75°
67°
13
73°
69°
14
75°
69°
15
81°
70°
16
86°
63°
17
79°
62°
18
77°
65°
19
80°
60°
20
78°
60°
21
80°
62°
22
81°
64°
23
N/A
24
78°
55°
25
78°
60°
26
83°
61°
27
82°
58°
28
80°
58°
29
77°
63°
30
77°
62°
31
78°
58°
1
76°
57°
2
75°
60°
3
76°
57°
4
75°
59°
5
79°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
August Weather in Ottawa
Ottawa's August 2026 forecast shows daily high temperatures ranging from 75° to 83°, with overnight lows between 55° and 63°. The average high for August is 78° with an average low of 59°. 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.
