S
M
T
W
T
F
S
29
45°
33°
30
42°
32°
1
42°
35°
2
44°
23°
3
47°
19°
4
41°
18°
5
33°
18°
6
32°
19°
7
32°
18°
8
33°
15°
9
32°
14°
10
28°
16°
11
28°
16°
12
30°
17°
13
30°
18°
14
31°
23°
15
32°
24°
16
34°
21°
17
36°
23°
18
36°
29°
19
37°
28°
20
37°
27°
21
36°
25°
22
36°
27°
23
35°
21°
24
36°
20°
25
35°
26°
26
36°
21°
27
34°
16°
28
31°
15°
29
33°
22°
30
30°
12°
31
31°
22°
1
33°
22°
2
Hist. Avg.
33°
17°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Gary
Gary's December 2026 forecast shows daily high temperatures ranging from 28° to 47°, with overnight lows between 12° and 35°. The average high for December is 35° with an average low of 22°. 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 Gary. See also: January | February | March.
