S
M
T
W
T
F
S
26
58°
38°
27
69°
37°
28
55°
48°
29
52°
42°
30
43°
37°
1
42°
30°
2
43°
28°
3
54°
28°
4
70°
42°
5
68°
49°
6
53°
40°
7
51°
34°
8
55°
35°
9
59°
44°
10
58°
38°
11
54°
32°
12
62°
29°
13
65°
41°
14
42°
39°
15
63°
41°
16
74°
46°
17
81°
60°
18
86°
66°
19
81°
65°
20
68°
46°
21
59°
41°
22
59°
38°
23
54°
42°
24
59°
53°
25
71°
46°
26
77°
58°
27
77°
51°
28
68°
45°
29
66°
39°
30
56°
42°
31
62°
47°
1
65°
51°
2
67°
49°
3
70°
54°
4
70°
55°
5
69°
58°
6
71°
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 56° to 77°, with overnight lows between 39° and 61°. The average high for May is 68° 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.
