S
M
T
W
T
F
S
30
83°
63°
31
84°
66°
1
88°
66°
2
88°
65°
3
87°
65°
4
87°
59°
5
82°
59°
6
82°
60°
7
83°
61°
8
84°
64°
9
85°
62°
10
82°
63°
11
86°
62°
12
86°
63°
13
85°
63°
14
85°
62°
15
86°
63°
16
86°
62°
17
85°
62°
18
85°
60°
19
84°
58°
20
83°
53°
21
78°
54°
22
77°
59°
23
77°
58°
24
83°
52°
25
77°
52°
26
77°
54°
27
76°
52°
28
79°
53°
29
80°
56°
30
81°
56°
1
79°
55°
2
79°
55°
3
75°
55°
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 75° to 88°, with overnight lows between 52° and 66°. The average high for September is 82° with an average low of 59°. 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.
