S
M
T
W
T
F
S
29
21°
9°
30
24°
9°
1
26°
5°
2
26°
-6°
3
24°
-8°
4
15°
-5°
5
9°
-4°
6
10°
3°
7
20°
2°
8
19°
1°
9
22°
-2°
10
21°
2°
11
17°
0°
12
18°
3°
13
17°
4°
14
21°
4°
15
20°
-1°
16
19°
-12°
17
19°
0°
18
14°
-1°
19
13°
-2°
20
13°
5°
21
21°
-2°
22
21°
-1°
23
17°
2°
24
18°
-10°
25
19°
-13°
26
7°
-16°
27
3°
-17°
28
1°
-16°
29
2°
-5°
30
18°
-3°
31
18°
-8°
1
Hist. Avg.
13°
-4°
2
Hist. Avg.
12°
-4°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Summit
Summit's December 2026 forecast shows daily high temperatures ranging from 1° to 26°, with overnight lows between -17° and 9°. The average high for December is 17° with an average low of -3°. 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 Summit. See also: January | February | March.
