S
M
T
W
T
F
S
26
57°
39°
27
62°
40°
28
56°
42°
29
58°
41°
30
60°
44°
1
58°
41°
2
56°
42°
3
61°
41°
4
58°
43°
5
66°
46°
6
61°
45°
7
63°
42°
8
67°
41°
9
62°
45°
10
64°
50°
11
73°
49°
12
65°
48°
13
65°
50°
14
74°
49°
15
66°
44°
16
66°
44°
17
67°
49°
18
75°
53°
19
74°
47°
20
71°
44°
21
65°
44°
22
67°
48°
23
67°
45°
24
71°
52°
25
77°
55°
26
78°
54°
27
70°
53°
28
69°
54°
29
70°
54°
30
69°
53°
31
70°
55°
1
80°
56°
2
78°
55°
3
78°
57°
4
77°
56°
5
78°
54°
6
80°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Lehigh Valley
Lehigh Valley's May 2026 forecast shows daily high temperatures ranging from 56° to 80°, with overnight lows between 39° and 57°. The average high for May is 68° with an average low of 48°. 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 Lehigh Valley. See also: June | July | August.