S
M
T
W
T
F
S
29
72°
48°
30
72°
47°
1
68°
46°
2
67°
47°
3
68°
46°
4
67°
49°
5
67°
54°
6
72°
55°
7
74°
54°
8
76°
46°
9
75°
48°
10
65°
52°
11
68°
51°
12
71°
54°
13
72°
51°
14
74°
43°
15
74°
44°
16
64°
46°
17
65°
51°
18
68°
51°
19
72°
52°
20
72°
52°
21
73°
51°
22
73°
53°
23
74°
52°
24
74°
52°
25
73°
50°
26
72°
51°
27
71°
49°
28
72°
50°
29
68°
43°
30
72°
40°
31
73°
39°
1
61°
42°
2
62°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Umatilla
Umatilla's December 2026 forecast shows daily high temperatures ranging from 61° to 76°, with overnight lows between 39° and 55°. The average high for December is 70° with an average low of 49°. 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 Umatilla. See also: January | February | March.
