S
M
T
W
T
F
S
29
77°
50°
30
80°
49°
1
71°
49°
2
68°
54°
3
70°
60°
4
77°
62°
5
80°
56°
6
82°
48°
7
77°
49°
8
69°
58°
9
72°
54°
10
77°
53°
11
72°
56°
12
69°
57°
13
77°
46°
14
77°
47°
15
69°
48°
16
66°
48°
17
68°
47°
18
67°
47°
19
66°
49°
20
67°
49°
21
71°
54°
22
72°
49°
23
69°
47°
24
69°
45°
25
66°
45°
26
65°
47°
27
65°
44°
28
67°
45°
29
66°
44°
30
65°
45°
31
67°
47°
1
64°
46°
2
65°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Weslaco
Weslaco's December 2026 forecast shows daily high temperatures ranging from 64° to 82°, with overnight lows between 44° and 62°. The average high for December is 71° with an average low of 50°. 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 Weslaco. See also: January | February | March.