S
M
T
W
T
F
S
26
69°
37°
27
59°
38°
28
61°
44°
29
69°
38°
30
79°
42°
1
73°
46°
2
67°
49°
3
89°
50°
4
73°
51°
5
67°
51°
6
71°
52°
7
70°
46°
8
70°
45°
9
76°
50°
10
70°
43°
11
77°
48°
12
80°
52°
13
74°
48°
14
73°
50°
15
67°
48°
16
66°
47°
17
72°
51°
18
71°
50°
19
68°
49°
20
70°
48°
21
64°
49°
22
65°
44°
23
66°
45°
24
71°
47°
25
70°
50°
26
65°
44°
27
66°
45°
28
68°
48°
29
69°
53°
30
73°
52°
31
76°
54°
1
77°
54°
2
76°
51°
3
67°
46°
4
75°
51°
5
76°
47°
6
67°
46°
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 64° to 80°, with overnight lows between 43° and 54°. The average high for May is 71° with an average low of 48°. 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.
