S
M
T
W
T
F
S
30
103°
72°
31
102°
72°
1
102°
74°
2
102°
75°
3
100°
75°
4
100°
72°
5
103°
72°
6
104°
74°
7
101°
77°
8
102°
78°
9
101°
71°
10
87°
66°
11
94°
72°
12
96°
72°
13
99°
73°
14
95°
67°
15
84°
59°
16
84°
61°
17
87°
65°
18
86°
63°
19
85°
60°
20
82°
58°
21
88°
65°
22
87°
65°
23
88°
64°
24
87°
65°
25
77°
64°
26
80°
63°
27
81°
63°
28
83°
64°
29
80°
63°
30
81°
54°
1
72°
50°
2
71°
49°
3
71°
48°
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 71° to 102°, with overnight lows between 48° and 78°. The average high for September is 86° with an average low of 64°. 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.
