S
M
T
W
T
F
S
26
86°
57°
27
86°
64°
28
79°
64°
29
75°
61°
30
66°
50°
1
68°
45°
2
70°
43°
3
72°
37°
4
81°
54°
5
75°
57°
6
73°
54°
7
68°
48°
8
75°
43°
9
81°
54°
10
84°
57°
11
75°
50°
12
81°
45°
13
82°
55°
14
73°
46°
15
82°
48°
16
86°
68°
17
88°
63°
18
90°
72°
19
91°
73°
20
82°
68°
21
81°
66°
22
79°
68°
23
84°
68°
24
80°
69°
25
76°
69°
26
78°
70°
27
86°
69°
28
82°
69°
29
78°
64°
30
76°
62°
31
78°
59°
1
75°
60°
2
77°
58°
3
79°
58°
4
80°
61°
5
81°
60°
6
84°
62°
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 75° to 86°, with overnight lows between 58° and 70°. The average high for May is 79° with an average low of 64°. 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.
