S
M
T
W
T
F
S
30
81°
61°
31
84°
62°
1
83°
58°
2
79°
56°
3
78°
56°
4
79°
54°
5
79°
54°
6
81°
60°
7
83°
57°
8
81°
56°
9
83°
58°
10
83°
54°
11
82°
57°
12
83°
59°
13
83°
59°
14
82°
58°
15
83°
58°
16
81°
57°
17
82°
58°
18
81°
57°
19
80°
56°
20
79°
56°
21
80°
55°
22
79°
49°
23
76°
53°
24
74°
56°
25
72°
55°
26
Hist. Avg.
77°
56°
27
Hist. Avg.
76°
55°
28
Hist. Avg.
76°
55°
29
Hist. Avg.
76°
54°
30
Hist. Avg.
75°
54°
1
Hist. Avg.
75°
54°
2
Hist. Avg.
75°
53°
3
Hist. Avg.
74°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in New Castle
New Castle's September 2026 forecast shows daily high temperatures ranging from 72° to 84°, with overnight lows between 49° and 62°. The average high for September is 80° with an average low of 57°. 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 New Castle. See also: October | November | December.
