S
M
T
W
T
F
S
30
101°
76°
31
101°
79°
1
100°
77°
2
98°
75°
3
89°
74°
4
93°
75°
5
96°
76°
6
98°
77°
7
98°
77°
8
100°
75°
9
97°
77°
10
99°
76°
11
95°
74°
12
97°
74°
13
95°
76°
14
94°
73°
15
89°
68°
16
92°
72°
17
93°
73°
18
84°
69°
19
87°
72°
20
91°
72°
21
92°
71°
22
91°
71°
23
91°
72°
24
90°
71°
25
91°
69°
26
90°
66°
27
81°
60°
28
80°
60°
29
80°
61°
30
85°
64°
1
88°
67°
2
88°
61°
3
78°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Duncanville
Duncanville's September 2026 forecast shows daily high temperatures ranging from 78° to 100°, with overnight lows between 57° and 77°. The average high for September is 91° 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 Duncanville. See also: October | November | December.