S
M
T
W
T
F
S
26
56°
45°
27
66°
43°
28
66°
48°
29
53°
45°
30
58°
42°
1
49°
39°
2
50°
33°
3
64°
33°
4
77°
49°
5
62°
46°
6
57°
45°
7
59°
40°
8
64°
39°
9
72°
48°
10
64°
41°
11
58°
35°
12
66°
36°
13
59°
47°
14
67°
45°
15
72°
39°
16
79°
51°
17
87°
63°
18
89°
68°
19
87°
67°
20
70°
50°
21
60°
42°
22
61°
46°
23
58°
55°
24
70°
56°
25
74°
53°
26
81°
60°
27
80°
59°
28
72°
54°
29
73°
54°
30
72°
53°
31
71°
54°
1
74°
57°
2
76°
54°
3
76°
59°
4
77°
58°
5
78°
59°
6
77°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Ottawa
Ottawa's May 2026 forecast shows daily high temperatures ranging from 70° to 81°, with overnight lows between 53° and 60°. The average high for May is 75° with an average low of 56°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how May weather will actually feel in Ottawa. See also: June | July | August.
