S
M
T
W
T
F
S
26
63°
46°
27
70°
48°
28
61°
48°
29
59°
48°
30
66°
52°
1
75°
50°
2
73°
52°
3
68°
57°
4
59°
54°
5
61°
50°
6
55°
46°
7
57°
48°
8
64°
46°
9
68°
50°
10
55°
43°
11
54°
41°
12
63°
41°
13
54°
46°
14
54°
46°
15
57°
45°
16
57°
45°
17
64°
48°
18
59°
48°
19
64°
52°
20
68°
55°
21
75°
55°
22
82°
59°
23
83°
56°
24
79°
57°
25
82°
59°
26
86°
54°
27
68°
48°
28
72°
63°
29
82°
61°
30
80°
60°
31
79°
59°
1
78°
60°
2
69°
54°
3
70°
53°
4
69°
54°
5
64°
47°
6
64°
45°
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 86°, with overnight lows between 45° and 63°. The average high for May is 75° with an average low of 55°. 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.
