S
M
T
W
T
F
S
26
64°
36°
27
72°
37°
28
74°
47°
29
70°
49°
30
56°
43°
1
53°
36°
2
48°
39°
3
51°
37°
4
62°
39°
5
73°
47°
6
47°
42°
7
53°
37°
8
51°
39°
9
63°
40°
10
60°
44°
11
53°
41°
12
54°
38°
13
53°
38°
14
53°
48°
15
67°
50°
16
75°
52°
17
77°
50°
18
77°
67°
19
79°
68°
20
71°
36°
21
56°
44°
22
65°
47°
23
62°
47°
24
65°
50°
25
69°
49°
26
66°
51°
27
67°
52°
28
72°
52°
29
73°
53°
30
71°
46°
31
65°
49°
1
68°
50°
2
68°
51°
3
67°
50°
4
65°
52°
5
68°
53°
6
73°
52°
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 56° to 79°, with overnight lows between 36° and 68°. The average high for May is 69° with an average low of 51°. 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.
