S
M
T
W
T
F
S
29
43°
27°
30
43°
34°
1
53°
30°
2
53°
33°
3
46°
35°
4
54°
25°
5
55°
27°
6
41°
24°
7
40°
28°
8
41°
23°
9
42°
20°
10
38°
19°
11
35°
20°
12
35°
19°
13
36°
21°
14
37°
20°
15
36°
21°
16
36°
23°
17
37°
24°
18
37°
29°
19
39°
32°
20
42°
30°
21
41°
25°
22
40°
23°
23
36°
23°
24
37°
25°
25
36°
28°
26
42°
26°
27
40°
25°
28
39°
24°
29
37°
23°
30
37°
22°
31
41°
14°
1
Hist. Avg.
38°
25°
2
Hist. Avg.
38°
25°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Brookline
Brookline's December 2026 forecast shows daily high temperatures ranging from 35° to 55°, with overnight lows between 14° and 35°. The average high for December is 41° with an average low of 25°. 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 Brookline. See also: January | February | March.
