S
M
T
W
T
F
S
26
58°
27°
27
59°
36°
28
63°
33°
29
66°
31°
30
71°
32°
1
74°
33°
2
78°
39°
3
80°
38°
4
76°
40°
5
72°
43°
6
78°
37°
7
74°
41°
8
69°
38°
9
70°
35°
10
73°
36°
11
72°
36°
12
81°
36°
13
66°
45°
14
63°
41°
15
57°
31°
16
54°
31°
17
58°
29°
18
62°
37°
19
67°
42°
20
71°
40°
21
70°
33°
22
79°
47°
23
84°
50°
24
82°
48°
25
79°
46°
26
64°
44°
27
77°
48°
28
83°
52°
29
85°
48°
30
81°
47°
31
79°
45°
1
83°
47°
2
83°
52°
3
85°
50°
4
78°
48°
5
72°
48°
6
72°
43°
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 64° to 85°, with overnight lows between 43° and 52°. The average high for May is 79° with an average low of 48°. 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.
