S
M
T
W
T
F
S
26
58°
45°
27
59°
40°
28
64°
44°
29
59°
40°
30
60°
44°
1
66°
45°
2
61°
41°
3
62°
44°
4
68°
50°
5
72°
51°
6
72°
52°
7
73°
53°
8
74°
54°
9
75°
53°
10
74°
50°
11
64°
48°
12
66°
51°
13
70°
52°
14
66°
49°
15
67°
49°
16
72°
54°
17
75°
55°
18
70°
46°
19
70°
45°
20
67°
46°
21
68°
45°
22
68°
46°
23
69°
48°
24
68°
55°
25
71°
51°
26
75°
54°
27
78°
50°
28
71°
59°
29
71°
59°
30
82°
51°
31
74°
56°
1
73°
56°
2
76°
53°
3
74°
56°
4
80°
55°
5
82°
53°
6
74°
53°
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 58° to 82°, with overnight lows between 40° and 59°. The average high for May is 70° with an average low of 50°. 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.
