S
M
T
W
T
F
S
29
46°
31°
30
44°
30°
1
43°
30°
2
43°
29°
3
44°
27°
4
42°
28°
5
42°
30°
6
48°
39°
7
52°
40°
8
56°
36°
9
57°
32°
10
44°
29°
11
45°
34°
12
46°
30°
13
44°
30°
14
39°
29°
15
42°
25°
16
39°
25°
17
38°
23°
18
38°
24°
19
39°
30°
20
40°
37°
21
46°
31°
22
52°
29°
23
46°
37°
24
50°
36°
25
54°
35°
26
49°
32°
27
43°
29°
28
45°
25°
29
43°
29°
30
37°
19°
31
49°
18°
1
32°
20°
2
37°
22°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Gaithersburg
Gaithersburg's December 2026 forecast shows daily high temperatures ranging from 32° to 57°, with overnight lows between 18° and 40°. The average high for December is 44° with an average low of 29°. 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 Gaithersburg. See also: January | February | March.
