S
M
T
W
T
F
S
30
79°
55°
31
77°
54°
1
77°
55°
2
79°
58°
3
78°
55°
4
78°
54°
5
79°
54°
6
78°
56°
7
76°
52°
8
77°
51°
9
74°
58°
10
76°
51°
11
75°
50°
12
75°
50°
13
76°
55°
14
78°
56°
15
81°
56°
16
81°
55°
17
80°
56°
18
81°
55°
19
80°
48°
20
75°
47°
21
71°
51°
22
72°
53°
23
75°
53°
24
78°
54°
25
77°
48°
26
76°
44°
27
74°
46°
28
69°
45°
29
69°
45°
30
67°
44°
1
Hist. Avg.
72°
46°
2
Hist. Avg.
71°
46°
3
Hist. Avg.
71°
45°
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 67° to 81°, with overnight lows between 44° and 58°. The average high for September is 76° with an average low of 52°. 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.
