S
M
T
W
T
F
S
30
82°
56°
31
83°
55°
1
82°
53°
2
81°
53°
3
83°
55°
4
87°
52°
5
83°
53°
6
84°
54°
7
85°
56°
8
87°
53°
9
84°
56°
10
82°
52°
11
80°
56°
12
84°
55°
13
85°
56°
14
86°
55°
15
85°
54°
16
79°
51°
17
82°
51°
18
Hist. Avg.
87°
61°
19
Hist. Avg.
87°
61°
20
Hist. Avg.
86°
60°
21
Hist. Avg.
86°
60°
22
Hist. Avg.
86°
60°
23
Hist. Avg.
86°
59°
24
Hist. Avg.
85°
59°
25
Hist. Avg.
85°
58°
26
Hist. Avg.
84°
58°
27
Hist. Avg.
84°
58°
28
Hist. Avg.
84°
57°
29
Hist. Avg.
84°
57°
30
Hist. Avg.
83°
57°
1
Hist. Avg.
83°
56°
2
Hist. Avg.
83°
56°
3
Hist. Avg.
82°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Monticello
Monticello's September 2026 forecast shows daily high temperatures ranging from 79° to 87°, with overnight lows between 51° and 56°. The average high for September is 83° with an average low of 54°. 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.
