S
M
T
W
T
F
S
26
99°
71°
27
96°
69°
28
100°
69°
29
69°
57°
30
62°
54°
1
63°
53°
2
78°
49°
3
79°
55°
4
92°
61°
5
95°
57°
6
72°
50°
7
82°
47°
8
88°
57°
9
96°
64°
10
88°
59°
11
84°
56°
12
92°
60°
13
98°
65°
14
97°
67°
15
93°
74°
16
92°
69°
17
90°
75°
18
98°
68°
19
74°
61°
20
75°
61°
21
76°
61°
22
81°
62°
23
87°
64°
24
88°
63°
25
85°
65°
26
87°
66°
27
84°
63°
28
83°
64°
29
82°
64°
30
88°
63°
31
85°
68°
1
85°
68°
2
86°
66°
3
84°
62°
4
83°
60°
5
84°
65°
6
85°
69°
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 74° to 98°, with overnight lows between 60° and 75°. The average high for May is 84° with an average low of 65°. 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.
