S
M
T
W
T
F
S
26
80°
54°
27
84°
59°
28
61°
52°
29
63°
46°
30
66°
43°
1
66°
46°
2
66°
45°
3
81°
43°
4
80°
62°
5
64°
47°
6
63°
44°
7
68°
42°
8
76°
50°
9
81°
52°
10
68°
49°
11
78°
43°
12
79°
50°
13
79°
56°
14
80°
50°
15
82°
67°
16
86°
70°
17
85°
69°
18
85°
74°
19
76°
54°
20
61°
54°
21
70°
56°
22
76°
62°
23
73°
59°
24
80°
56°
25
84°
60°
26
80°
62°
27
83°
66°
28
80°
65°
29
77°
62°
30
79°
60°
31
80°
56°
1
80°
61°
2
81°
57°
3
82°
62°
4
81°
62°
5
82°
62°
6
84°
64°
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 77° to 84°, with overnight lows between 56° and 66°. The average high for May is 81° with an average low of 61°. 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.
