S
M
T
W
T
F
S
26
70°
45°
27
62°
46°
28
54°
41°
29
62°
37°
30
58°
43°
1
59°
40°
2
68°
33°
3
76°
53°
4
80°
48°
5
60°
46°
6
62°
37°
7
73°
43°
8
79°
51°
9
77°
48°
10
74°
43°
11
84°
47°
12
81°
57°
13
80°
46°
14
83°
59°
15
92°
59°
16
85°
57°
17
84°
60°
18
60°
51°
19
62°
45°
20
59°
42°
21
67°
50°
22
74°
55°
23
78°
53°
24
83°
61°
25
85°
64°
26
84°
62°
27
79°
63°
28
75°
63°
29
77°
61°
30
76°
61°
31
77°
57°
1
77°
57°
2
82°
60°
3
79°
62°
4
83°
61°
5
80°
62°
6
80°
65°
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 85°, with overnight lows between 53° and 65°. The average high for May is 80° with an average low of 61°. 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.
