S
M
T
W
T
F
S
30
87°
58°
31
81°
59°
1
82°
60°
2
86°
64°
3
85°
64°
4
85°
62°
5
83°
63°
6
85°
64°
7
85°
62°
8
84°
61°
9
83°
61°
10
81°
59°
11
82°
58°
12
83°
61°
13
83°
62°
14
Hist. Avg.
81°
60°
15
Hist. Avg.
81°
60°
16
Hist. Avg.
80°
59°
17
Hist. Avg.
80°
59°
18
Hist. Avg.
79°
58°
19
Hist. Avg.
79°
58°
20
Hist. Avg.
79°
58°
21
Hist. Avg.
78°
57°
22
Hist. Avg.
78°
57°
23
Hist. Avg.
77°
56°
24
Hist. Avg.
77°
56°
25
Hist. Avg.
76°
56°
26
Hist. Avg.
76°
55°
27
Hist. Avg.
76°
55°
28
Hist. Avg.
75°
54°
29
Hist. Avg.
75°
54°
30
Hist. Avg.
75°
54°
1
Hist. Avg.
74°
53°
2
Hist. Avg.
74°
53°
3
Hist. Avg.
74°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Mount Vernon
Mount Vernon's September 2026 forecast shows daily high temperatures ranging from 81° to 87°, with overnight lows between 58° and 64°. The average high for September is 84° with an average low of 61°. 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 Mount Vernon. See also: October | November | December.
