S
M
T
W
T
F
S
26
48°
38°
27
60°
38°
28
49°
34°
29
65°
34°
30
61°
40°
1
65°
33°
2
74°
33°
3
78°
43°
4
82°
39°
5
49°
41°
6
53°
40°
7
77°
37°
8
78°
49°
9
81°
41°
10
73°
47°
11
88°
50°
12
83°
52°
13
85°
41°
14
88°
56°
15
95°
47°
16
87°
53°
17
75°
52°
18
53°
42°
19
65°
37°
20
61°
45°
21
61°
50°
22
71°
48°
23
75°
50°
24
89°
58°
25
88°
58°
26
81°
56°
27
77°
55°
28
77°
52°
29
78°
50°
30
83°
54°
31
83°
58°
1
83°
57°
2
82°
55°
3
81°
52°
4
82°
57°
5
76°
57°
6
76°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Herndon
Herndon's May 2026 forecast shows daily high temperatures ranging from 61° to 89°, with overnight lows between 48° and 58°. The average high for May is 79° with an average low of 54°. 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 Herndon. See also: June | July | August.
