Where is the sea warmest in the Baltic in September?
In September the warmest sea in the Baltic is at Gdańsk, Poland, at 17.9°C. Nowhere in the region is comfortable for swimming this month — not one of the 90 cities measured reaches 19.0°C.
| # | City | Country | Sea | Swimming |
|---|---|---|---|---|
| 1 | Gdańsk | Poland | 17.9°C | Bracing |
| 2 | Gdynia | Poland | 17.8°C | Bracing |
| 3 | Świnoujście | Poland | 17.8°C | Bracing |
| 4 | Wolin | Poland | 17.8°C | Bracing |
| 5 | Universitäts- und Hansestadt Greifswald | Germany | 17.8°C | Bracing |
| 6 | Wolgast | Germany | 17.8°C | Bracing |
| 7 | Svetlogorsk | Russia | 17.8°C | Bracing |
| 8 | Reda | Poland | 17.8°C | Bracing |
| 9 | Klaipėda | Lithuania | 17.7°C | Bracing |
| 10 | Zelenogradsk | Russia | 17.7°C | Bracing |
| 11 | Władysławowo | Poland | 17.7°C | Bracing |
| 12 | Bergen auf Rügen | Germany | 17.6°C | Bracing |
| 13 | Palanga | Lithuania | 17.6°C | Bracing |
| 14 | Faaborg | Denmark | 17.5°C | Bracing |
| 15 | Kappeln | Germany | 17.5°C | Bracing |
| 16 | Sønderborg | Denmark | 17.5°C | Bracing |
| 17 | Koszalin | Poland | 17.4°C | Bracing |
| 18 | Darłowo | Poland | 17.4°C | Bracing |
| 19 | Kamień Pomorski | Poland | 17.4°C | Bracing |
| 20 | Ustka | Poland | 17.3°C | Bracing |
| 21 | Rønne | Denmark | 17.3°C | Bracing |
| 22 | Oldenburg in Holstein | Germany | 17.3°C | Bracing |
| 23 | Kołobrzeg | Poland | 17.2°C | Bracing |
| 24 | Trzebiatów | Poland | 17.2°C | Bracing |
| 25 | Fehmarn | Germany | 17.2°C | Bracing |
Ranked on the NOAA OISST monthly climatology — a long-run average for September, not a forecast. A given September will run warmer or cooler than this, and the sea is warmest late in the afternoon and late in the season.