S
M
T
W
T
F
S
30
72°
52°
31
76°
55°
1
79°
48°
2
74°
47°
3
71°
48°
4
72°
52°
5
74°
56°
6
77°
54°
7
77°
52°
8
71°
54°
9
69°
55°
10
72°
54°
11
71°
52°
12
73°
53°
13
71°
52°
14
68°
46°
15
67°
45°
16
67°
44°
17
68°
47°
18
67°
51°
19
70°
51°
20
71°
52°
21
72°
47°
22
66°
43°
23
65°
49°
24
64°
50°
25
70°
43°
26
62°
47°
27
68°
48°
28
69°
46°
29
62°
48°
30
Hist. Avg.
64°
43°
1
Hist. Avg.
64°
43°
2
Hist. Avg.
64°
42°
3
Hist. Avg.
63°
42°
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 62° to 79°, with overnight lows between 43° and 56°. The average high for September is 70° with an average low of 50°. 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.
