S
M
T
W
T
F
S
29
51°
39°
30
55°
38°
1
54°
37°
2
53°
32°
3
42°
31°
4
48°
30°
5
53°
37°
6
49°
34°
7
41°
25°
8
39°
22°
9
38°
22°
10
39°
27°
11
39°
32°
12
41°
27°
13
42°
24°
14
38°
20°
15
38°
26°
16
39°
28°
17
40°
29°
18
45°
26°
19
44°
21°
20
39°
20°
21
36°
19°
22
36°
22°
23
40°
25°
24
39°
23°
25
37°
19°
26
36°
16°
27
35°
18°
28
34°
18°
29
35°
17°
30
36°
21°
31
40°
18°
1
40°
16°
2
34°
13°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Bethlehem
Bethlehem's December 2026 forecast shows daily high temperatures ranging from 34° to 55°, with overnight lows between 13° and 39°. The average high for December is 41° with an average low of 25°. 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 Bethlehem. See also: January | February | March.