S
M
T
W
T
F
S
26
85°
69°
27
88°
71°
28
84°
67°
29
65°
58°
30
63°
53°
1
57°
49°
2
69°
52°
3
76°
55°
4
79°
61°
5
83°
66°
6
86°
59°
7
74°
56°
8
74°
55°
9
78°
60°
10
82°
63°
11
82°
61°
12
81°
63°
13
84°
66°
14
82°
65°
15
85°
67°
16
85°
67°
17
84°
66°
18
85°
67°
19
86°
68°
20
86°
68°
21
83°
67°
22
79°
65°
23
80°
65°
24
85°
68°
25
84°
66°
26
80°
61°
27
79°
62°
28
81°
67°
29
83°
68°
30
86°
67°
31
87°
69°
1
89°
69°
2
89°
70°
3
90°
71°
4
91°
71°
5
90°
70°
6
87°
67°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Allen
Allen's May 2026 forecast shows daily high temperatures ranging from 57° to 91°, with overnight lows between 49° and 71°. The average high for May is 81° with an average low of 64°. 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 Allen. See also: June | July | August.