S
M
T
W
T
F
S
29
34°
22°
30
35°
18°
1
33°
12°
2
30°
12°
3
26°
10°
4
28°
8°
5
26°
10°
6
24°
13°
7
24°
16°
8
27°
10°
9
26°
7°
10
23°
4°
11
20°
15°
12
36°
14°
13
27°
17°
14
31°
19°
15
Hist. Avg.
25°
6°
16
Hist. Avg.
25°
6°
17
Hist. Avg.
24°
5°
18
Hist. Avg.
24°
5°
19
Hist. Avg.
24°
4°
20
Hist. Avg.
24°
4°
21
Hist. Avg.
23°
4°
22
Hist. Avg.
23°
3°
23
Hist. Avg.
23°
3°
24
Hist. Avg.
23°
3°
25
Hist. Avg.
23°
2°
26
Hist. Avg.
23°
2°
27
Hist. Avg.
22°
2°
28
Hist. Avg.
22°
1°
29
Hist. Avg.
22°
1°
30
Hist. Avg.
22°
1°
31
Hist. Avg.
22°
0°
1
Hist. Avg.
23°
1°
2
Hist. Avg.
23°
0°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
December Weather in Castlebar
Castlebar's December 2026 forecast shows daily high temperatures ranging from 20° to 36°, with overnight lows between 4° and 22°. The average high for December is 28° with an average low of 13°. 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 Castlebar. See also: January | February | March.
