S
M
T
W
T
F
S
26
73°
48°
27
73°
48°
28
61°
43°
29
60°
38°
30
55°
35°
1
55°
33°
2
64°
42°
3
70°
45°
4
68°
48°
5
69°
41°
6
62°
40°
7
57°
38°
8
62°
41°
9
64°
44°
10
63°
45°
11
75°
41°
12
68°
46°
13
65°
44°
14
65°
44°
15
66°
49°
16
74°
52°
17
76°
56°
18
78°
56°
19
74°
52°
20
72°
54°
21
69°
53°
22
71°
55°
23
77°
59°
24
78°
58°
25
77°
56°
26
76°
54°
27
76°
57°
28
79°
59°
29
80°
60°
30
81°
61°
31
82°
61°
1
82°
62°
2
83°
63°
3
83°
62°
4
77°
59°
5
75°
57°
6
78°
63°
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 55° to 83°, with overnight lows between 33° and 63°. The average high for May is 71° 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.
