S
M
T
W
T
F
S
29
36°
21°
30
28°
21°
1
35°
22°
2
35°
21°
3
30°
20°
4
30°
19°
5
29°
17°
6
27°
18°
7
33°
11°
8
22°
8°
9
19°
12°
10
25°
17°
11
31°
16°
12
31°
17°
13
30°
17°
14
31°
16°
15
31°
16°
16
32°
15°
17
31°
15°
18
30°
14°
19
27°
13°
20
20°
12°
21
26°
9°
22
27°
-1°
23
20°
-2°
24
13°
-9°
25
12°
-1°
26
13°
11°
27
28°
8°
28
29°
-5°
29
27°
-9°
30
14°
-10°
31
8°
-9°
1
7°
-7°
2
10°
0°
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 7° to 36°, with overnight lows between -10° and 22°. The average high for December is 25° with an average low of 10°. 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.
