S
M
T
W
T
F
S
28
87°
58°
29
89°
61°
30
93°
65°
1
91°
63°
2
92°
60°
3
96°
64°
4
98°
69°
5
96°
73°
6
96°
65°
7
95°
64°
8
95°
61°
9
98°
66°
10
104°
72°
11
101°
68°
12
100°
75°
13
100°
72°
14
105°
70°
15
106°
68°
16
102°
63°
17
98°
64°
18
98°
67°
19
96°
67°
20
98°
66°
21
97°
65°
22
99°
67°
23
100°
66°
24
99°
67°
25
101°
68°
26
98°
63°
27
99°
68°
28
99°
67°
29
98°
67°
30
97°
66°
31
94°
64°
1
93°
65°
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 93° to 106°, with overnight lows between 63° and 72°. The average high for July is 99° with an average low of 67°. 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.