S
M
T
W
T
F
S
29
50°
37°
30
46°
37°
1
58°
31°
2
50°
36°
3
51°
26°
4
61°
25°
5
53°
25°
6
42°
24°
7
45°
29°
8
46°
24°
9
45°
23°
10
42°
22°
11
40°
23°
12
39°
24°
13
41°
24°
14
41°
25°
15
42°
25°
16
42°
26°
17
43°
25°
18
42°
35°
19
47°
32°
20
46°
31°
21
42°
26°
22
42°
24°
23
41°
26°
24
42°
25°
25
40°
22°
26
38°
26°
27
39°
24°
28
40°
23°
29
39°
22°
30
38°
20°
31
42°
17°
1
Hist. Avg.
43°
26°
2
Hist. Avg.
43°
25°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Manassas
Manassas's December 2026 forecast shows daily high temperatures ranging from 38° to 61°, with overnight lows between 17° and 37°. The average high for December is 44° 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 Manassas. See also: January | February | March.
