S
M
T
W
T
F
S
29
40°
23°
30
39°
22°
1
39°
21°
2
40°
23°
3
42°
25°
4
45°
27°
5
48°
31°
6
44°
29°
7
39°
29°
8
37°
28°
9
38°
27°
10
37°
27°
11
50°
32°
12
47°
29°
13
50°
25°
14
49°
21°
15
36°
22°
16
37°
23°
17
35°
24°
18
37°
31°
19
43°
33°
20
47°
35°
21
48°
32°
22
49°
32°
23
47°
35°
24
50°
32°
25
51°
24°
26
51°
22°
27
35°
21°
28
36°
29°
29
44°
31°
30
45°
33°
31
47°
34°
1
48°
30°
2
50°
23°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Southwest
Southwest's December 2026 forecast shows daily high temperatures ranging from 35° to 51°, with overnight lows between 21° and 35°. 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 Southwest. See also: January | February | March.
