In December warmest sea in Slovenia is usually observed in the following locations: Portoroz, Piran, Strunjan.
Table below shows the average sea water temperature for marine resorts of Slovenia in December for the last three years.
| Place name | December 2025 | December 2024 | December 2023 |
|---|---|---|---|
| Portoroz | 56.9°F | 56.5°F | 56.6°F |
| Piran | 56.9°F | 56.5°F | 56.6°F |
| Strunjan | 56.7°F | 56.2°F | 56.3°F |
| Isola | 56.4°F | 55.9°F | 55.9°F |
| Dolenjske Toplice | 56.3°F | 57.1°F | 57.4°F |
| Koper | 56.1°F | 55.7°F | 55.7°F |
| Cerkno | 54.5°F | 54.0°F | 54.9°F |
| Bohinjsko Jezero | 54.3°F | 53.8°F | 54.8°F |
Charts below show average sea water temperature for Slovenia resorts with the warmest sea in December.
You can also check other months of the year to see sea temperature of Slovenia resorts at that time.
Places in Slovenia:
Name
°F
