S
M
T
W
T
F
S
26
58°
51°
27
70°
50°
28
69°
49°
29
64°
58°
30
67°
45°
1
68°
44°
2
63°
42°
3
65°
38°
4
77°
47°
5
81°
53°
6
74°
61°
7
67°
48°
8
71°
41°
9
77°
45°
10
83°
49°
11
66°
50°
12
73°
44°
13
75°
48°
14
58°
47°
15
75°
45°
16
82°
50°
17
90°
60°
18
93°
62°
19
94°
66°
20
94°
67°
21
82°
59°
22
59°
54°
23
56°
51°
24
68°
54°
25
76°
65°
26
75°
63°
27
80°
65°
28
82°
59°
29
83°
56°
30
69°
52°
31
69°
50°
1
72°
51°
2
73°
52°
3
79°
54°
4
77°
56°
5
77°
59°
6
80°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in New Castle
New Castle's May 2026 forecast shows daily high temperatures ranging from 69° to 83°, with overnight lows between 50° and 65°. The average high for May is 76° 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 May weather will actually feel in New Castle. See also: June | July | August.
