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
68°
48°
3
88°
54°
4
73°
53°
5
73°
50°
6
77°
48°
7
73°
49°
8
71°
50°
9
77°
50°
10
78°
51°
11
80°
51°
12
74°
48°
13
72°
50°
14
73°
48°
15
69°
48°
16
65°
51°
17
71°
48°
18
63°
43°
19
64°
43°
20
66°
46°
21
75°
49°
22
71°
48°
23
69°
46°
24
75°
52°
25
69°
49°
26
67°
47°
27
75°
54°
28
76°
54°
29
75°
53°
30
76°
53°
31
77°
54°
1
76°
53°
2
75°
52°
3
75°
50°
4
71°
47°
5
69°
46°
6
68°
48°
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 63° to 88°, with overnight lows between 43° and 54°. The average high for May is 73° with an average low of 50°. 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.
