S
M
T
W
T
F
S
26
41°
15°
27
41°
15°
28
42°
16°
29
43°
17°
30
44°
19°
1
45°
19°
2
47°
21°
3
46°
20°
4
47°
22°
5
48°
23°
6
48°
23°
7
51°
24°
8
49°
25°
9
51°
25°
10
51°
26°
11
52°
25°
12
52°
25°
13
54°
27°
14
53°
30°
15
52°
28°
16
52°
28°
17
55°
33°
18
58°
33°
19
56°
31°
20
57°
36°
21
60°
37°
22
64°
38°
23
65°
31°
24
58°
33°
25
62°
34°
26
59°
35°
27
64°
34°
28
59°
33°
29
60°
34°
30
63°
37°
31
63°
36°
1
65°
41°
2
68°
40°
3
67°
39°
4
65°
42°
5
68°
43°
6
70°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Richardson
Richardson's May 2026 forecast shows daily high temperatures ranging from 41° to 70°, with overnight lows between 15° and 45°. The average high for May is 55° with an average low of 29°. 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 Richardson. See also: June | July | August.