S
M
T
W
T
F
S
30
84°
65°
31
85°
64°
1
87°
60°
2
80°
59°
3
78°
60°
4
84°
65°
5
82°
60°
6
76°
58°
7
79°
65°
8
78°
64°
9
79°
64°
10
82°
62°
11
77°
59°
12
79°
62°
13
80°
62°
14
76°
58°
15
77°
59°
16
77°
61°
17
75°
60°
18
82°
59°
19
77°
54°
20
73°
55°
21
77°
60°
22
80°
59°
23
81°
59°
24
78°
54°
25
71°
58°
26
72°
54°
27
70°
52°
28
71°
53°
29
70°
52°
30
70°
53°
1
71°
52°
2
68°
49°
3
67°
48°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Chantilly
Chantilly's September 2026 forecast shows daily high temperatures ranging from 67° to 87°, with overnight lows between 48° and 65°. The average high for September is 77° with an average low of 58°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Chantilly. See also: October | November | December.
