Average sea water temperature in December:
+55.2°F
| Minimum sea water temperature in December: | 60.1°F |
| Maximum sea water temperature in December: | 50.2°F |
Daily sea water temperature in December, °F
Show year:
2025
2024
2023
The average sea water temperature in December of 2025 was 55.9°F. The highest and lowest sea temperatures during the month were 56.8°F and 54.7°F.
Monthly sea water temperature in Koper, °F
Which Slovenia resorts have warmest sea in December?
| Place name | December 2025 | December 2024 |
|---|---|---|
| Portoroz | 56.6°F | 56.5°F |
| Piran | 56.6°F | 56.5°F |
| Strunjan | 56.4°F | 56.2°F |
| Dolenjske Toplice | 56.2°F | 57.1°F |
| Isola | 56.2°F | 55.9°F |
| Koper | 55.9°F | 55.7°F |
| Cerkno | 54.4°F | 54.0°F |
| Bohinjsko Jezero | 54.2°F | 53.8°F |
Best time for vacation in Koper
Koper on a weather map
Places in Slovenia:
Name
°F
24 Hours Forecast
Koper
Local time: 13:21
December 21, sunday
1500
54°F
SW
2 mph
2 mph
1800
46°F
W
4 mph
4 mph
2100
41°F
W
4 mph
4 mph
December 22, monday
0000
39°F
W
5 mph
5 mph
0300
39°F
W
5 mph
5 mph
0600
41°F
W
4 mph
4 mph
0900
43°F
W
4 mph
4 mph
1200
48°F
W
3 mph
3 mph
