S
M
T
W
T
F
S
26
56°
41°
27
56°
41°
28
57°
38°
29
62°
36°
30
61°
33°
1
65°
30°
2
71°
33°
3
75°
35°
4
70°
45°
5
66°
40°
6
55°
35°
7
70°
29°
8
78°
37°
9
76°
45°
10
79°
44°
11
85°
54°
12
91°
43°
13
90°
45°
14
85°
51°
15
84°
42°
16
81°
50°
17
67°
44°
18
50°
39°
19
61°
35°
20
69°
35°
21
74°
37°
22
67°
35°
23
77°
35°
24
83°
44°
25
78°
44°
26
71°
56°
27
84°
50°
28
88°
54°
29
82°
45°
30
70°
45°
31
76°
46°
1
81°
51°
2
81°
51°
3
83°
51°
4
87°
53°
5
86°
54°
6
87°
53°
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 70° to 88°, with overnight lows between 45° and 54°. The average high for May is 82° with an average low of 50°. 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.
