S
M
T
W
T
F
S
26
60°
45°
27
61°
42°
28
62°
44°
29
62°
42°
30
63°
41°
1
64°
51°
2
73°
50°
3
66°
48°
4
64°
44°
5
64°
42°
6
66°
46°
7
65°
48°
8
68°
52°
9
72°
46°
10
65°
44°
11
66°
45°
12
67°
48°
13
67°
47°
14
66°
50°
15
68°
51°
16
68°
52°
17
72°
56°
18
75°
56°
19
77°
52°
20
69°
48°
21
70°
53°
22
72°
49°
23
72°
49°
24
71°
50°
25
74°
54°
26
79°
53°
27
76°
55°
28
80°
57°
29
81°
58°
30
81°
57°
31
74°
58°
1
73°
58°
2
74°
58°
3
75°
53°
4
80°
59°
5
82°
61°
6
83°
61°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Allentown
Allentown's May 2026 forecast shows daily high temperatures ranging from 60° to 83°, with overnight lows between 41° and 61°. The average high for May is 71° with an average low of 51°. 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 Allentown. See also: June | July | August.
