S
M
T
W
T
F
S
30
80°
54°
31
76°
50°
1
72°
50°
2
72°
51°
3
73°
49°
4
71°
51°
5
71°
49°
6
72°
49°
7
72°
51°
8
77°
54°
9
73°
54°
10
69°
51°
11
70°
54°
12
73°
49°
13
74°
53°
14
75°
52°
15
69°
48°
16
68°
48°
17
66°
47°
18
68°
53°
19
73°
53°
20
Hist. Avg.
67°
48°
21
Hist. Avg.
67°
47°
22
Hist. Avg.
66°
47°
23
Hist. Avg.
66°
46°
24
Hist. Avg.
65°
46°
25
Hist. Avg.
65°
46°
26
Hist. Avg.
64°
45°
27
Hist. Avg.
64°
45°
28
Hist. Avg.
63°
44°
29
Hist. Avg.
63°
44°
30
Hist. Avg.
62°
44°
1
Hist. Avg.
62°
43°
2
Hist. Avg.
61°
43°
3
Hist. Avg.
61°
42°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Fairfax
Fairfax's September 2026 forecast shows daily high temperatures ranging from 66° to 80°, with overnight lows between 47° and 54°. The average high for September is 72° with an average low of 51°. 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.
