S
M
T
W
T
F
S
29
52°
38°
30
55°
38°
1
53°
39°
2
54°
37°
3
51°
32°
4
46°
28°
5
52°
35°
6
53°
36°
7
43°
32°
8
39°
26°
9
39°
23°
10
38°
25°
11
37°
32°
12
39°
30°
13
40°
27°
14
37°
20°
15
36°
25°
16
38°
29°
17
40°
32°
18
39°
28°
19
44°
24°
20
39°
20°
21
37°
19°
22
34°
21°
23
34°
25°
24
36°
25°
25
37°
24°
26
35°
18°
27
34°
17°
28
33°
12°
29
32°
15°
30
32°
26°
31
39°
21°
1
41°
17°
2
32°
13°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Monongahela
Monongahela's December 2026 forecast shows daily high temperatures ranging from 32° to 55°, with overnight lows between 12° and 39°. The average high for December is 41° with an average low of 26°. 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 Monongahela. See also: January | February | March.