S
M
T
W
T
F
S
26
60°
46°
27
63°
44°
28
63°
43°
29
62°
47°
30
63°
46°
1
63°
45°
2
65°
46°
3
64°
43°
4
63°
42°
5
62°
42°
6
65°
43°
7
66°
47°
8
69°
49°
9
68°
49°
10
67°
46°
11
66°
44°
12
63°
45°
13
65°
44°
14
64°
45°
15
66°
45°
16
67°
46°
17
67°
49°
18
69°
48°
19
69°
47°
20
68°
47°
21
70°
51°
22
70°
51°
23
71°
57°
24
75°
58°
25
79°
57°
26
78°
56°
27
78°
59°
28
80°
58°
29
82°
57°
30
82°
52°
31
73°
53°
1
72°
52°
2
74°
53°
3
76°
60°
4
81°
60°
5
81°
59°
6
75°
60°
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 82°, with overnight lows between 42° and 60°. The average high for May is 70° with an average low of 50°. 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.
