S
M
T
W
T
F
S
26
59°
44°
27
72°
38°
28
63°
43°
29
62°
49°
30
68°
48°
1
66°
42°
2
64°
48°
3
63°
44°
4
74°
47°
5
84°
57°
6
72°
60°
7
69°
52°
8
72°
44°
9
69°
54°
10
83°
48°
11
64°
49°
12
70°
39°
13
78°
55°
14
67°
53°
15
70°
51°
16
83°
63°
17
89°
65°
18
91°
68°
19
95°
72°
20
93°
63°
21
74°
54°
22
59°
51°
23
67°
55°
24
69°
57°
25
72°
60°
26
79°
61°
27
79°
60°
28
78°
61°
29
79°
68°
30
80°
62°
31
79°
61°
1
80°
62°
2
76°
62°
3
73°
63°
4
75°
63°
5
77°
60°
6
76°
63°
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 59° to 95°, with overnight lows between 51° and 72°. The average high for May is 78° with an average low of 62°. 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.
