S
M
T
W
T
F
S
29
43°
28°
30
43°
25°
1
44°
28°
2
42°
28°
3
42°
26°
4
41°
29°
5
41°
26°
6
42°
24°
7
38°
22°
8
35°
23°
9
36°
23°
10
39°
29°
11
42°
24°
12
48°
24°
13
Hist. Avg.
42°
26°
14
Hist. Avg.
42°
25°
15
Hist. Avg.
42°
25°
16
Hist. Avg.
42°
25°
17
Hist. Avg.
41°
25°
18
Hist. Avg.
41°
24°
19
Hist. Avg.
41°
24°
20
Hist. Avg.
40°
24°
21
Hist. Avg.
40°
24°
22
Hist. Avg.
40°
24°
23
Hist. Avg.
40°
24°
24
Hist. Avg.
40°
23°
25
Hist. Avg.
39°
23°
26
Hist. Avg.
39°
23°
27
Hist. Avg.
39°
23°
28
Hist. Avg.
39°
22°
29
Hist. Avg.
39°
22°
30
Hist. Avg.
38°
22°
31
Hist. Avg.
38°
22°
1
Hist. Avg.
38°
22°
2
Hist. Avg.
38°
21°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
December Weather in New Castle Northwest
New Castle Northwest's December 2026 forecast shows daily high temperatures ranging from 35° to 48°, with overnight lows between 22° and 29°. The average high for December is 41° with an average low of 26°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how December weather will actually feel in New Castle Northwest. See also: January | February | March.
