S
M
T
W
T
F
S
30
95°
68°
31
90°
70°
1
93°
71°
2
93°
72°
3
94°
71°
4
93°
72°
5
93°
71°
6
91°
70°
7
91°
70°
8
90°
69°
9
90°
68°
10
89°
67°
11
91°
69°
12
91°
68°
13
92°
70°
14
92°
68°
15
Hist. Avg.
87°
64°
16
Hist. Avg.
87°
64°
17
Hist. Avg.
86°
64°
18
Hist. Avg.
86°
63°
19
Hist. Avg.
86°
63°
20
Hist. Avg.
85°
62°
21
Hist. Avg.
85°
62°
22
Hist. Avg.
84°
61°
23
Hist. Avg.
84°
61°
24
Hist. Avg.
84°
60°
25
Hist. Avg.
83°
60°
26
Hist. Avg.
83°
60°
27
Hist. Avg.
83°
59°
28
Hist. Avg.
82°
59°
29
Hist. Avg.
82°
58°
30
Hist. Avg.
82°
58°
1
Hist. Avg.
81°
58°
2
Hist. Avg.
81°
57°
3
Hist. Avg.
80°
57°
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 89° to 95°, with overnight lows between 67° and 72°. The average high for September is 92° with an average low of 70°. 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.
