S
M
T
W
T
F
S
26
62°
33°
27
69°
49°
28
65°
44°
29
50°
33°
30
49°
32°
1
44°
31°
2
46°
32°
3
49°
38°
4
55°
41°
5
56°
40°
6
53°
39°
7
54°
39°
8
52°
38°
9
53°
39°
10
54°
42°
11
60°
43°
12
64°
47°
13
65°
39°
14
57°
37°
15
57°
37°
16
58°
39°
17
59°
41°
18
62°
48°
19
66°
42°
20
59°
40°
21
60°
39°
22
60°
40°
23
61°
42°
24
65°
50°
25
71°
47°
26
63°
44°
27
62°
43°
28
63°
48°
29
69°
51°
30
73°
51°
31
68°
50°
1
71°
51°
2
74°
54°
3
75°
53°
4
75°
49°
5
65°
47°
6
66°
50°
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 44° to 75°, with overnight lows between 31° and 54°. The average high for May is 61° with an average low of 43°. 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.
