S
M
T
W
T
F
S
29
40°
35°
30
43°
30°
1
46°
25°
2
40°
34°
3
40°
30°
4
49°
27°
5
39°
29°
6
44°
38°
7
46°
34°
8
50°
28°
9
47°
29°
10
39°
31°
11
41°
35°
12
45°
33°
13
47°
32°
14
43°
34°
15
43°
32°
16
49°
26°
17
49°
25°
18
38°
23°
19
39°
21°
20
37°
30°
21
39°
33°
22
47°
32°
23
45°
33°
24
46°
31°
25
44°
27°
26
40°
22°
27
35°
23°
28
37°
26°
29
39°
22°
30
37°
19°
31
35°
30°
1
45°
14°
2
48°
12°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Harrisburg
Harrisburg's December 2026 forecast shows daily high temperatures ranging from 35° to 50°, with overnight lows between 12° and 38°. The average high for December is 43° with an average low of 28°. 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 Harrisburg. See also: January | February | March.
