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