S
M
T
W
T
F
S
29
40°
25°
30
38°
25°
1
39°
30°
2
44°
36°
3
48°
34°
4
47°
28°
5
42°
28°
6
38°
29°
7
37°
29°
8
37°
30°
9
38°
28°
10
37°
28°
11
37°
26°
12
36°
27°
13
36°
28°
14
42°
33°
15
47°
29°
16
47°
32°
17
41°
30°
18
47°
33°
19
48°
35°
20
47°
30°
21
45°
32°
22
47°
34°
23
47°
32°
24
46°
34°
25
44°
27°
26
45°
22°
27
37°
22°
28
35°
30°
29
38°
26°
30
39°
32°
31
40°
34°
1
44°
33°
2
47°
29°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Hermiston
Hermiston's December 2026 forecast shows daily high temperatures ranging from 35° to 48°, with overnight lows between 22° and 36°. The average high for December is 42° 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 Hermiston. See also: January | February | March.
