S
M
T
W
T
F
S
29
43°
27°
30
45°
30°
1
49°
35°
2
49°
32°
3
50°
33°
4
53°
37°
5
54°
27°
6
42°
25°
7
41°
33°
8
53°
37°
9
53°
35°
10
47°
36°
11
50°
37°
12
51°
34°
13
44°
28°
14
40°
24°
15
38°
24°
16
38°
25°
17
40°
29°
18
43°
33°
19
50°
33°
20
48°
35°
21
51°
33°
22
41°
30°
23
41°
29°
24
49°
35°
25
37°
22°
26
37°
26°
27
38°
29°
28
39°
31°
29
52°
28°
30
51°
26°
31
39°
26°
1
40°
23°
2
40°
19°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Glendora
Glendora's December 2026 forecast shows daily high temperatures ranging from 37° to 54°, with overnight lows between 19° and 37°. The average high for December is 45° with an average low of 30°. 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 Glendora. See also: January | February | March.