Average sea water temperature in December:
+55.7°F
| Minimum sea water temperature in December: | 61.0°F |
| Maximum sea water temperature in December: | 50.4°F |
Daily sea water temperature in December, °F
Show year:
2025
2024
2023
The average sea water temperature in December of 2025 was 56.3°F. The highest and lowest sea temperatures during the month were 57.9°F and 55.0°F.
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| Portoroz |
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Monthly sea water temperature in Portoroz, °F
Which Slovenia resorts have warmest sea in December?
| Place name | December 2025 | December 2024 |
|---|---|---|
| Portoroz | 56.3°F | 56.5°F |
| Piran | 56.3°F | 56.5°F |
| Strunjan | 56.1°F | 56.2°F |
| Dolenjske Toplice | 56.0°F | 57.1°F |
| Isola | 55.9°F | 55.9°F |
| Koper | 55.6°F | 55.7°F |
| Cerkno | 53.9°F | 54.0°F |
| Bohinjsko Jezero | 53.8°F | 53.8°F |
Best time for vacation in Portoroz
Portoroz on a weather map
Places in Slovenia:
Name
°F
24 Hours Forecast
Portoroz
Local time: 22:04
December 30, tuesday
0000

34°F
NW
3 mph
3 mph
0300

34°F
NW
4 mph
4 mph
0600

34°F
W
5 mph
5 mph
0900

36°F
W
5 mph
5 mph
1200

46°F
SW
12 mph
12 mph
1500

43°F
W
14 mph
14 mph
1800

37°F
W
19 mph
19 mph
2100

30°F
W
14 mph
14 mph

























