S
M
T
W
T
F
S
29
50°
42°
30
48°
42°
1
49°
41°
2
51°
42°
3
51°
36°
4
45°
36°
5
45°
37°
6
44°
36°
7
44°
36°
8
45°
35°
9
44°
35°
10
45°
36°
11
48°
40°
12
49°
40°
13
48°
39°
14
49°
38°
15
49°
39°
16
46°
39°
17
46°
40°
18
48°
40°
19
48°
39°
20
47°
40°
21
49°
39°
22
48°
38°
23
48°
39°
24
46°
38°
25
47°
39°
26
46°
40°
27
48°
40°
28
49°
39°
29
49°
40°
30
48°
41°
31
49°
39°
1
49°
38°
2
47°
37°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Portrush
Portrush's December 2026 forecast shows daily high temperatures ranging from 44° to 51°, with overnight lows between 35° and 42°. The average high for December is 47° with an average low of 39°. 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 Portrush. See also: January | February | March.