Water temperature of the Baltic Sea in september Where to swim in the Baltic Sea in september 2025?
Several countries border the seaside of the Baltic Sea, including: Germany, Denmark, Estonia, Finland, Lapland, Latvia, Lithuania, Poland, Russia and Sweden. We measure the water temperature daily in these countries and archive it in order to calculate monthly averages, like those of the month of september.
Several countries border the seaside of the Baltic Sea, including: Germany, Denmark, Estonia, Finland, Lapland, Latvia, Lithuania, Poland, Russia and Sweden.
We measure the water temperature daily in these countries and archive it in order to calculate monthly averages, like those of the month of september.
The seasonal average for the water temperature in the month of september is between 50°F and 64°F. The lowest sea temperature measured this month is 31°F and the highest is 70°F.
The sea temperature map of the Baltic Sea in september
The map below presents a monthly average of the water temperature of the Baltic Sea for the month of september for several coastal cities. You can zoom and move around on the map. By clicking on the markers, you can see sea temperature details by city in september.
ideal swimming 
pleasant swimming 
cool swimming 
cold swimming 
freezing swimmingWhere can you swim in the Baltic Sea in september?
Below, see the average temperatures measured in september in the different countries on the shores of the Baltic Sea.
Germany
62°F to 64°F
cool swimmingDenmark
61°F to 63°F
cool swimmingEstonia
60°F to 63°F
cold swimmingFinland
50°F to 60°F
cold swimmingLapland
54°F to 56°F
freezing swimmingLatvia
61°F to 63°F
cold swimmingLithuania
63°F to 64°F
cool swimmingPoland
63°F to 64°F
cool swimmingRussia
58°F to 63°F
cool swimmingSweden
54°F to 62°F
cold swimmingWater temperature of the Baltic Sea: choose another month
See monthly seasonal averages of the water temperature of the Baltic Sea by clicking on the links below: