S
M
T
W
T
F
S
26
59°
39°
27
68°
43°
28
55°
46°
29
59°
48°
30
63°
46°
1
72°
46°
2
70°
52°
3
66°
52°
4
54°
43°
5
61°
37°
6
52°
41°
7
54°
45°
8
64°
41°
9
63°
39°
10
54°
37°
11
52°
32°
12
59°
36°
13
54°
39°
14
55°
41°
15
54°
41°
16
59°
43°
17
61°
48°
18
61°
45°
19
65°
51°
20
65°
50°
21
74°
53°
22
78°
55°
23
79°
55°
24
74°
53°
25
73°
53°
26
70°
51°
27
73°
55°
28
71°
52°
29
67°
50°
30
66°
48°
31
67°
49°
1
60°
47°
2
61°
47°
3
64°
51°
4
65°
53°
5
67°
54°
6
68°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Waterloo
Waterloo's May 2026 forecast shows daily high temperatures ranging from 60° to 79°, with overnight lows between 47° and 55°. The average high for May is 69° with an average low of 52°. 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 Waterloo. See also: June | July | August.
