S
M
T
W
T
F
S
30
90°
69°
31
89°
68°
1
90°
69°
2
85°
68°
3
86°
68°
4
85°
67°
5
87°
68°
6
87°
68°
7
86°
67°
8
84°
64°
9
84°
62°
10
83°
63°
11
83°
65°
12
86°
65°
13
87°
66°
14
87°
61°
15
86°
60°
16
83°
61°
17
82°
60°
18
84°
61°
19
86°
60°
20
86°
60°
21
85°
64°
22
85°
64°
23
84°
61°
24
84°
58°
25
83°
58°
26
83°
57°
27
82°
60°
28
84°
62°
29
85°
61°
30
85°
61°
1
84°
60°
2
84°
61°
3
85°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Fairfax
Fairfax's September 2026 forecast shows daily high temperatures ranging from 82° to 90°, with overnight lows between 57° and 69°. The average high for September is 85° with an average low of 63°. 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 Fairfax. See also: October | November | December.
