S
M
T
W
T
F
S
30
80°
59°
31
85°
55°
1
85°
56°
2
84°
56°
3
84°
57°
4
85°
54°
5
78°
58°
6
83°
58°
7
84°
57°
8
84°
57°
9
82°
56°
10
78°
55°
11
76°
55°
12
80°
56°
13
81°
55°
14
82°
56°
15
82°
57°
16
77°
55°
17
73°
49°
18
Hist. Avg.
82°
58°
19
Hist. Avg.
82°
57°
20
Hist. Avg.
81°
57°
21
Hist. Avg.
81°
56°
22
Hist. Avg.
80°
56°
23
Hist. Avg.
80°
56°
24
Hist. Avg.
80°
55°
25
Hist. Avg.
79°
55°
26
Hist. Avg.
79°
54°
27
Hist. Avg.
78°
54°
28
Hist. Avg.
78°
54°
29
Hist. Avg.
78°
53°
30
Hist. Avg.
77°
53°
1
Hist. Avg.
77°
52°
2
Hist. Avg.
76°
52°
3
Hist. Avg.
76°
52°
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 73° to 85°, with overnight lows between 49° and 59°. The average high for September is 81° with an average low of 56°. 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.
