S
M
T
W
T
F
S
29
44°
20°
30
43°
19°
1
43°
17°
2
41°
17°
3
42°
18°
4
42°
24°
5
44°
23°
6
48°
30°
7
49°
22°
8
43°
21°
9
41°
24°
10
47°
24°
11
46°
17°
12
Hist. Avg.
46°
21°
13
Hist. Avg.
46°
21°
14
Hist. Avg.
46°
21°
15
Hist. Avg.
46°
21°
16
Hist. Avg.
46°
20°
17
Hist. Avg.
46°
20°
18
Hist. Avg.
46°
20°
19
Hist. Avg.
46°
20°
20
Hist. Avg.
46°
20°
21
Hist. Avg.
46°
20°
22
Hist. Avg.
46°
20°
23
Hist. Avg.
46°
20°
24
Hist. Avg.
46°
20°
25
Hist. Avg.
46°
20°
26
Hist. Avg.
46°
20°
27
Hist. Avg.
46°
21°
28
Hist. Avg.
46°
21°
29
Hist. Avg.
46°
21°
30
Hist. Avg.
46°
21°
31
Hist. Avg.
46°
21°
1
Hist. Avg.
46°
21°
2
Hist. Avg.
46°
21°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
December Weather in Boulder
Boulder's December 2026 forecast shows daily high temperatures ranging from 41° to 49°, with overnight lows between 17° and 30°. The average high for December is 44° with an average low of 21°. 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 Boulder. See also: January | February | March.
