S
M
T
W
T
F
S
30
81°
67°
31
91°
72°
1
92°
72°
2
94°
72°
3
95°
73°
4
94°
71°
5
92°
71°
6
81°
62°
7
81°
59°
8
86°
59°
9
84°
66°
10
75°
62°
11
80°
54°
12
87°
64°
13
82°
58°
14
75°
47°
15
95°
62°
16
85°
70°
17
89°
69°
18
77°
67°
19
74°
63°
20
77°
58°
21
68°
59°
22
69°
51°
23
62°
56°
24
73°
57°
25
69°
51°
26
74°
46°
27
77°
42°
28
80°
46°
29
79°
48°
30
71°
60°
1
87°
63°
2
70°
49°
3
70°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Monticello
Monticello'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 Monticello. See also: October | November | December.
