S
M
T
W
T
F
S
30
96°
74°
31
95°
73°
1
95°
75°
2
94°
75°
3
95°
74°
4
94°
73°
5
92°
74°
6
93°
73°
7
94°
73°
8
93°
72°
9
92°
71°
10
88°
71°
11
91°
70°
12
93°
72°
13
91°
71°
14
91°
71°
15
90°
70°
16
89°
70°
17
85°
69°
18
85°
69°
19
86°
68°
20
89°
68°
21
86°
60°
22
86°
57°
23
85°
57°
24
86°
60°
25
88°
62°
26
87°
65°
27
88°
65°
28
89°
60°
29
81°
66°
30
90°
56°
1
88°
57°
2
74°
59°
3
73°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Duncan
Duncan's September 2026 forecast shows daily high temperatures ranging from 73° to 96°, with overnight lows between 56° and 75°. The average high for September is 89° with an average low of 67°. 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 Duncan. See also: October | November | December.
