S
M
T
W
T
F
S
26
55°
41°
27
64°
45°
28
64°
50°
29
52°
36°
30
50°
32°
1
45°
32°
2
57°
30°
3
66°
42°
4
75°
42°
5
55°
35°
6
51°
35°
7
53°
35°
8
56°
39°
9
61°
39°
10
58°
43°
11
62°
42°
12
63°
43°
13
66°
46°
14
65°
47°
15
66°
46°
16
69°
47°
17
73°
51°
18
66°
51°
19
69°
53°
20
71°
53°
21
69°
44°
22
63°
43°
23
64°
45°
24
65°
45°
25
65°
46°
26
66°
46°
27
65°
47°
28
66°
46°
29
67°
51°
30
68°
56°
31
74°
52°
1
70°
53°
2
73°
57°
3
76°
58°
4
78°
58°
5
78°
59°
6
77°
60°
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 51° to 78°, with overnight lows between 35° and 60°. The average high for May is 67° 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.
