S
M
T
W
T
F
S
26
66°
52°
27
72°
47°
28
78°
46°
29
78°
50°
30
86°
52°
1
86°
54°
2
73°
55°
3
73°
54°
4
67°
55°
5
63°
52°
6
75°
74°
7
84°
55°
8
83°
52°
9
89°
55°
10
86°
53°
11
94°
57°
12
90°
57°
13
87°
55°
14
88°
56°
15
83°
54°
16
80°
53°
17
80°
53°
18
81°
55°
19
82°
54°
20
81°
54°
21
83°
53°
22
78°
51°
23
81°
53°
24
83°
53°
25
83°
54°
26
82°
52°
27
86°
53°
28
82°
52°
29
87°
58°
30
88°
59°
31
89°
59°
1
89°
58°
2
88°
59°
3
86°
59°
4
82°
58°
5
81°
57°
6
82°
55°
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 78° to 94°, with overnight lows between 51° and 59°. The average high for May is 84° with an average low of 55°. 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.
