S
M
T
W
T
F
S
26
93°
73°
27
91°
72°
28
95°
73°
29
91°
73°
30
90°
70°
31
90°
68°
1
84°
72°
2
91°
73°
3
88°
68°
4
86°
72°
5
90°
72°
6
88°
70°
7
88°
70°
8
91°
72°
9
92°
72°
10
90°
73°
11
91°
72°
12
91°
73°
13
93°
70°
14
93°
71°
15
94°
70°
16
93°
69°
17
91°
68°
18
92°
69°
19
91°
68°
20
91°
67°
21
92°
66°
22
91°
68°
23
92°
69°
24
90°
68°
25
91°
65°
26
91°
68°
27
92°
68°
28
92°
69°
29
91°
68°
30
91°
68°
31
88°
67°
1
86°
67°
2
87°
66°
3
87°
67°
4
89°
67°
5
89°
66°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Monticello
Monticello's August 2026 forecast shows daily high temperatures ranging from 86° to 94°, with overnight lows between 65° and 73°. The average high for August is 91° with an average low of 69°. 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 Monticello. See also: September | October | November.