S
M
T
W
T
F
S
26
92°
71°
27
91°
70°
28
92°
71°
29
92°
71°
30
91°
70°
31
91°
70°
1
87°
69°
2
88°
70°
3
87°
70°
4
91°
71°
5
92°
70°
6
93°
71°
7
88°
69°
8
91°
69°
9
90°
68°
10
91°
63°
11
86°
65°
12
87°
63°
13
86°
63°
14
90°
64°
15
86°
65°
16
85°
68°
17
86°
67°
18
90°
66°
19
88°
67°
20
84°
65°
21
84°
66°
22
85°
67°
23
86°
65°
24
89°
66°
25
89°
64°
26
88°
60°
27
84°
61°
28
83°
62°
29
84°
63°
30
83°
64°
31
86°
65°
1
88°
61°
2
83°
59°
3
81°
59°
4
81°
58°
5
82°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Mount Vernon
Mount Vernon's August 2026 forecast shows daily high temperatures ranging from 81° to 93°, with overnight lows between 58° and 71°. The average high for August is 87° with an average low of 66°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Mount Vernon. See also: September | October | November.
