S
M
T
W
T
F
S
29
64°
40°
30
66°
39°
1
65°
41°
2
65°
43°
3
68°
44°
4
69°
45°
5
70°
38°
6
64°
42°
7
67°
44°
8
71°
43°
9
71°
43°
10
70°
44°
11
70°
43°
12
69°
44°
13
70°
43°
14
71°
43°
15
70°
44°
16
70°
44°
17
69°
45°
18
71°
44°
19
71°
41°
20
70°
41°
21
66°
35°
22
62°
36°
23
61°
39°
24
64°
43°
25
65°
42°
26
64°
40°
27
63°
39°
28
63°
39°
29
65°
40°
30
65°
42°
31
66°
40°
1
65°
41°
2
66°
41°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Montclair
Montclair's December 2026 forecast shows daily high temperatures ranging from 61° to 71°, with overnight lows between 35° and 45°. The average high for December is 67° with an average low of 42°. 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 Montclair. See also: January | February | March.
