S
M
T
W
T
F
S
29
38°
31°
30
48°
34°
1
41°
34°
2
41°
33°
3
44°
33°
4
40°
32°
5
43°
32°
6
49°
31°
7
46°
30°
8
43°
26°
9
37°
25°
10
38°
28°
11
47°
20°
12
40°
15°
13
33°
13°
14
31°
21°
15
33°
14°
16
34°
26°
17
36°
27°
18
39°
24°
19
39°
26°
20
41°
26°
21
42°
27°
22
43°
26°
23
45°
16°
24
44°
12°
25
34°
12°
26
29°
17°
27
35°
25°
28
36°
25°
29
46°
28°
30
46°
29°
31
48°
28°
1
48°
14°
2
47°
11°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Lancaster
Lancaster's December 2026 forecast shows daily high temperatures ranging from 29° to 49°, with overnight lows between 11° and 34°. The average high for December is 41° with an average low of 24°. 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 Lancaster. See also: January | February | March.