S
M
T
W
T
F
S
31
86°
59°
1
87°
62°
2
86°
61°
3
88°
59°
4
77°
55°
5
82°
55°
6
82°
55°
7
83°
54°
8
82°
58°
9
82°
60°
10
87°
59°
11
83°
58°
12
85°
52°
13
75°
56°
14
75°
52°
15
82°
58°
16
81°
55°
17
80°
50°
18
78°
56°
19
81°
52°
20
78°
52°
21
76°
54°
22
79°
45°
23
68°
47°
24
76°
49°
25
74°
50°
26
74°
54°
27
76°
51°
28
67°
51°
29
69°
47°
30
73°
47°
1
72°
49°
2
77°
54°
3
79°
52°
4
65°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Monticello
Monticello's September 2025 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 Monticello. See also: October | November | December.
