S
M
T
W
T
F
S
26
81°
60°
27
78°
57°
28
80°
56°
29
82°
57°
30
91°
70°
1
81°
62°
2
83°
62°
3
78°
58°
4
79°
60°
5
82°
62°
6
83°
64°
7
82°
62°
8
84°
64°
9
86°
65°
10
86°
66°
11
85°
65°
12
82°
59°
13
79°
59°
14
81°
61°
15
82°
67°
16
85°
66°
17
87°
68°
18
84°
68°
19
82°
67°
20
83°
68°
21
84°
69°
22
87°
69°
23
88°
70°
24
89°
69°
25
89°
70°
26
88°
70°
27
90°
69°
28
90°
69°
29
90°
70°
30
92°
71°
31
93°
71°
1
92°
70°
2
93°
68°
3
92°
67°
4
89°
71°
5
91°
72°
6
93°
69°
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 78° to 93°, with overnight lows between 56° and 72°. The average high for May is 86° with an average low of 66°. 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.
