S
M
T
W
T
F
S
30
81°
62°
31
88°
71°
1
89°
73°
2
93°
71°
3
94°
73°
4
84°
70°
5
83°
68°
6
79°
59°
7
80°
57°
8
86°
60°
9
89°
71°
10
83°
68°
11
81°
67°
12
77°
64°
13
84°
54°
14
72°
55°
15
84°
66°
16
88°
64°
17
80°
62°
18
75°
55°
19
70°
51°
20
68°
48°
21
71°
49°
22
74°
51°
23
75°
52°
24
74°
50°
25
73°
54°
26
77°
54°
27
77°
55°
28
76°
54°
29
74°
54°
30
74°
53°
1
72°
50°
2
68°
52°
3
75°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Delaware
Delaware's September 2026 forecast shows daily high temperatures ranging from 68° to 88°, with overnight lows between 48° and 67°. The average high for September is 76° with an average low of 55°. 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 Delaware. See also: October | November | December.
