S
M
T
W
T
F
S
26
73°
52°
27
81°
46°
28
77°
59°
29
68°
54°
30
61°
43°
1
63°
36°
2
57°
36°
3
64°
32°
4
79°
50°
5
72°
57°
6
61°
48°
7
63°
41°
8
72°
36°
9
73°
54°
10
77°
54°
11
70°
46°
12
75°
43°
13
77°
52°
14
64°
41°
15
75°
39°
16
86°
59°
17
90°
64°
18
89°
69°
19
85°
64°
20
72°
59°
21
64°
57°
22
75°
63°
23
72°
63°
24
77°
62°
25
75°
61°
26
77°
61°
27
77°
59°
28
75°
58°
29
77°
59°
30
75°
57°
31
76°
61°
1
81°
62°
2
81°
62°
3
77°
61°
4
75°
58°
5
75°
56°
6
79°
63°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in McKinney
McKinney's May 2026 forecast shows daily high temperatures ranging from 64° to 90°, with overnight lows between 56° and 69°. The average high for May is 77° 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 McKinney. See also: June | July | August.