The Slovenia resorts with the warmest sea water temperature in May are Portoroz, Piran and Strunjan.
Below you can see a list of all popular Slovenia resorts and information about sea water temperature in May for the last two years.
| Resort Name | May 2026 | May 2025 | May 2024 |
|---|---|---|---|
| Portoroz | 63.8°F | 67.0°F | 66.1°F |
| Piran | 63.8°F | 67.0°F | 66.1°F |
| Strunjan | 63.6°F | 66.9°F | 65.9°F |
| Isola | 63.4°F | 66.8°F | 65.7°F |
| Koper | 63.3°F | 66.5°F | 65.6°F |
| Cerkno | 62.5°F | 64.7°F | 64.9°F |
| Bohinjsko Jezero | 62.4°F | 64.6°F | 64.8°F |
| Dolenjske Toplice | 62.1°F | 63.6°F | 65.6°F |
Please see following sea water temperature averages charts for the warmest Slovenia resorts in May.
You can also get the same information for the every other month of the year when the average sea water temperature is greater then 70°F.
Slovenia Resorts:
NAME
F°
| Bled |  |
+34 |
| Bohinjsko Jezero | |
+34 |
| Cerkno |  |
+36 |
| Dolenjske Toplice |  |
+50 |
| Isola | |
+50 |
| Koper | |
+50 |
| Kranjska Gora | |
+34 |
| Ljubljana | |
+46 |
| Maribor | |
+48 |
| Moravske Toplice | |
+50 |
| Piran | |
+50 |
| Portoroz | |
+50 |
| Postojna | |
+42 |
| Rogaska Slatina | |
+48 |
| Strunjan | |
+50 |
