S
M
T
W
T
F
S
30
91°
65°
31
93°
67°
1
95°
69°
2
97°
70°
3
99°
70°
4
99°
72°
5
94°
71°
6
83°
66°
7
88°
59°
8
90°
67°
9
91°
71°
10
80°
71°
11
88°
68°
12
81°
70°
13
90°
67°
14
82°
61°
15
95°
59°
16
96°
71°
17
93°
71°
18
93°
69°
19
91°
66°
20
93°
71°
21
90°
66°
22
N/A
23
71°
61°
24
N/A
25
77°
50°
26
75°
49°
27
76°
43°
28
79°
44°
29
82°
46°
30
86°
51°
1
88°
60°
2
74°
61°
3
73°
56°
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 ° to °, with overnight lows between ° and °. The average high for September is ° with an average low of °. 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.
