S
M
T
W
T
F
S
30
82°
60°
31
79°
61°
1
78°
66°
2
78°
67°
3
85°
66°
4
86°
67°
5
85°
64°
6
80°
60°
7
81°
64°
8
81°
58°
9
77°
57°
10
76°
57°
11
76°
58°
12
78°
56°
13
77°
62°
14
82°
58°
15
76°
55°
16
75°
57°
17
74°
56°
18
75°
60°
19
78°
53°
20
77°
56°
21
76°
56°
22
80°
53°
23
74°
52°
24
73°
52°
25
73°
53°
26
74°
58°
27
76°
58°
28
77°
57°
29
78°
50°
30
72°
51°
1
70°
57°
2
76°
57°
3
77°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Manassas
Manassas's September 2026 forecast shows daily high temperatures ranging from 70° to 86°, with overnight lows between 50° and 67°. 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 Manassas. See also: October | November | December.
