S
M
T
W
T
F
S
29
52°
29°
30
45°
27°
1
44°
30°
2
43°
32°
3
46°
30°
4
45°
28°
5
42°
25°
6
41°
24°
7
40°
23°
8
37°
22°
9
38°
19°
10
37°
20°
11
35°
28°
12
43°
25°
13
39°
28°
14
Hist. Avg.
41°
24°
15
Hist. Avg.
40°
24°
16
Hist. Avg.
40°
24°
17
Hist. Avg.
40°
24°
18
Hist. Avg.
40°
23°
19
Hist. Avg.
39°
23°
20
Hist. Avg.
39°
23°
21
Hist. Avg.
39°
22°
22
Hist. Avg.
38°
22°
23
Hist. Avg.
38°
22°
24
Hist. Avg.
38°
22°
25
Hist. Avg.
38°
22°
26
Hist. Avg.
38°
21°
27
Hist. Avg.
37°
21°
28
Hist. Avg.
37°
21°
29
Hist. Avg.
37°
21°
30
Hist. Avg.
37°
21°
31
Hist. Avg.
37°
20°
1
Hist. Avg.
36°
20°
2
Hist. Avg.
36°
20°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
December Weather in Allentown
Allentown's December 2026 forecast shows daily high temperatures ranging from 35° to 52°, with overnight lows between 19° and 32°. The average high for December is 42° 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 Allentown. See also: January | February | March.
