S
M
T
W
T
F
S
30
89°
66°
31
89°
67°
1
96°
71°
2
93°
72°
3
91°
71°
4
93°
70°
5
82°
67°
6
84°
62°
7
82°
59°
8
87°
55°
9
89°
60°
10
90°
71°
11
81°
68°
12
81°
69°
13
87°
70°
14
80°
56°
15
78°
50°
16
85°
56°
17
89°
65°
18
86°
67°
19
81°
66°
20
85°
69°
21
74°
65°
22
66°
58°
23
64°
55°
24
66°
50°
25
74°
50°
26
72°
57°
27
70°
61°
28
73°
62°
29
74°
57°
30
82°
53°
1
88°
58°
2
91°
59°
3
64°
56°
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 64° to 91°, with overnight lows between 56° and 59°. The average high for September is 81° 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.
