S
M
T
W
T
F
S
26
102°
77°
27
101°
77°
28
93°
74°
29
95°
71°
30
91°
71°
31
88°
66°
1
86°
63°
2
87°
64°
3
93°
68°
4
95°
68°
5
91°
67°
6
89°
66°
7
90°
67°
8
93°
71°
9
94°
72°
10
90°
71°
11
92°
71°
12
94°
70°
13
89°
68°
14
87°
69°
15
91°
70°
16
93°
70°
17
90°
69°
18
90°
70°
19
92°
69°
20
84°
68°
21
88°
69°
22
92°
69°
23
93°
70°
24
93°
69°
25
92°
71°
26
93°
71°
27
94°
70°
28
91°
69°
29
91°
68°
30
90°
68°
31
89°
67°
1
81°
67°
2
83°
66°
3
84°
66°
4
88°
67°
5
88°
67°
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 81° to 102°, with overnight lows between 63° and 77°. The average high for August is 91° with an average low of 69°. 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.
