Slovenia — Water Temperature in Seas, Lakes and Rivers
Check today’s water temperatures across Slovenia, including seas, lakes, and rivers. View real-time updates and seasonal ranges for both coastal and inland waters. We find every place where you can swim and show you the water temperature there today and throughout the year.
Sea Water Temperature Along the Coast
Chart of Average Temperature Changes Over the Last 60 Days
Places with the Warmest Sea Water Today
The Most Popular Seaside Places
Coastal Seas and Oceans
Water Temperature in Lakes and Rivers
Popular Lakes
Popular Rivers
Popular Places
Water Temperature and Swimming Overview
Regions and Map
Water Temperature Trends
Slovenia’s short Adriatic coast enjoys relatively mild sea temperatures that follow a clear seasonal cycle. In winter the sea along towns such as Piran and Portorož typically sits around 12–14 °C (54–57 °F), spring brings warming to roughly 13–18 °C (55–64 °F), while summer peaks commonly between 22–26 °C (72–79 °F). Autumn sees a gradual cooling back toward the teens Celsius. These summer temperatures make coastal swimming popular and comfortable for many visitors, with public beaches, monitored bathing areas and facilities operating during the warmer months. Water quality along the Slovenian coast is generally high and routinely checked, which supports widespread recreational use.
Swimming Conditions
In inland waters the picture is more varied because of altitude, depth and river source. Alpine and karst lakes such as Bled and Bohinj warm at the surface in summer to roughly 18–24 °C (64–75 °F), making them suitable for swimming, whereas deeper parts remain cooler. Rivers can be quite different: glacier- and snow-fed streams like the Soča often stay cold even in July and August, commonly ranging from about 8–16 °C (46–61 °F), while lowland rivers may warm toward the upper teens or low twenties Celsius in summer. Swimming in lakes and designated river spots is allowed and popular, but safety and conservation considerations matter: strong currents, low temperatures, sudden weather changes and protected areas can restrict access or make swimming risky. Visitors are advised to use marked bathing zones, heed local rules and be aware of temperature-related cold shock in mountain waters.