S
M
T
W
T
F
S
26
67°
38°
27
73°
37°
28
69°
48°
29
58°
44°
30
50°
38°
1
53°
30°
2
50°
36°
3
59°
36°
4
70°
44°
5
72°
47°
6
54°
43°
7
53°
37°
8
55°
38°
9
64°
46°
10
57°
39°
11
55°
39°
12
55°
38°
13
56°
41°
14
60°
44°
15
61°
46°
16
62°
47°
17
62°
47°
18
64°
49°
19
62°
47°
20
63°
48°
21
61°
42°
22
61°
42°
23
63°
43°
24
68°
47°
25
72°
50°
26
73°
52°
27
68°
47°
28
69°
43°
29
65°
44°
30
73°
54°
31
75°
54°
1
75°
51°
2
70°
50°
3
74°
54°
4
76°
55°
5
77°
56°
6
74°
52°
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 53° to 77°, with overnight lows between 37° and 56°. The average high for May is 65° with an average low of 47°. 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.
