S
M
T
W
T
F
S
26
52°
40°
27
51°
41°
28
50°
40°
29
52°
39°
30
54°
38°
1
56°
42°
2
54°
40°
3
53°
39°
4
58°
40°
5
56°
39°
6
57°
40°
7
61°
39°
8
55°
38°
9
56°
46°
10
61°
46°
11
58°
45°
12
63°
47°
13
66°
46°
14
64°
42°
15
58°
40°
16
61°
44°
17
64°
49°
18
69°
49°
19
70°
39°
20
58°
38°
21
59°
40°
22
60°
40°
23
61°
47°
24
67°
51°
25
72°
51°
26
70°
50°
27
64°
50°
28
64°
49°
29
65°
47°
30
64°
51°
31
72°
51°
1
66°
48°
2
65°
44°
3
68°
45°
4
69°
44°
5
71°
46°
6
74°
42°
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 50° to 74°, with overnight lows between 38° and 51°. The average high for May is 62° with an average low of 44°. 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.
