S
M
T
W
T
F
S
28
82°
67°
29
89°
69°
30
90°
68°
1
90°
62°
2
86°
62°
3
84°
69°
4
86°
70°
5
90°
63°
6
87°
62°
7
84°
65°
8
84°
63°
9
83°
63°
10
83°
64°
11
84°
63°
12
88°
64°
13
86°
68°
14
84°
67°
15
87°
64°
16
85°
64°
17
84°
70°
18
89°
70°
19
84°
67°
20
84°
69°
21
85°
69°
22
85°
68°
23
86°
64°
24
84°
64°
25
85°
65°
26
85°
68°
27
88°
68°
28
88°
64°
29
86°
64°
30
85°
65°
31
84°
64°
1
83°
63°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
July Weather in Herndon
Herndon's July 2026 forecast shows daily high temperatures ranging from 82° to 90°, with overnight lows between 62° and 70°. The average high for July 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 July weather will actually feel in Herndon. See also: August | September | October.
