S
M
T
W
T
F
S
30
85°
63°
31
84°
60°
1
83°
59°
2
82°
59°
3
83°
57°
4
83°
60°
5
83°
59°
6
81°
55°
7
Hist. Avg.
82°
59°
8
Hist. Avg.
81°
58°
9
Hist. Avg.
81°
58°
10
Hist. Avg.
81°
58°
11
Hist. Avg.
80°
57°
12
Hist. Avg.
80°
57°
13
Hist. Avg.
80°
57°
14
Hist. Avg.
80°
56°
15
Hist. Avg.
79°
56°
16
Hist. Avg.
79°
56°
17
Hist. Avg.
79°
55°
18
Hist. Avg.
78°
55°
19
Hist. Avg.
78°
54°
20
Hist. Avg.
78°
54°
21
Hist. Avg.
77°
54°
22
Hist. Avg.
77°
53°
23
Hist. Avg.
76°
53°
24
Hist. Avg.
76°
52°
25
Hist. Avg.
76°
52°
26
Hist. Avg.
75°
52°
27
Hist. Avg.
75°
51°
28
Hist. Avg.
74°
51°
29
Hist. Avg.
74°
50°
30
Hist. Avg.
74°
50°
1
Hist. Avg.
73°
50°
2
Hist. Avg.
73°
49°
3
Hist. Avg.
72°
49°
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 81° to 85°, with overnight lows between 55° and 63°. The average high for September is 83° with an average low of 59°. 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.
