S
M
T
W
T
F
S
26
94°
72°
27
95°
74°
28
95°
74°
29
94°
75°
30
96°
75°
31
96°
74°
1
95°
74°
2
96°
75°
3
96°
75°
4
97°
74°
5
97°
75°
6
96°
75°
7
97°
74°
8
96°
75°
9
96°
74°
10
95°
74°
11
97°
75°
12
97°
75°
13
96°
74°
14
97°
75°
15
96°
74°
16
97°
72°
17
92°
70°
18
92°
70°
19
91°
68°
20
90°
69°
21
91°
68°
22
87°
66°
23
88°
63°
24
88°
63°
25
87°
64°
26
87°
62°
27
88°
62°
28
87°
63°
29
89°
62°
30
92°
64°
31
93°
68°
1
93°
68°
2
92°
67°
3
93°
68°
4
93°
69°
5
92°
68°
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 87° to 97°, with overnight lows between 62° and 75°. The average high for August is 93° with an average low of 70°. 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.
