Where is the sea warmest in the Baltic?
The warmest water in the Baltic month by month, across 90 coastal cities — and how many of them are comfortable enough to swim in.
| Month | Warmest city | Sea | Comfortable |
|---|---|---|---|
| January | Kragerø | 5.3°C | nowhere |
| February | Rønne | 3.8°C | nowhere |
| March | Vejle | 5.1°C | nowhere |
| April | Świnoujście | 8.5°C | nowhere |
| May | Świnoujście | 13.3°C | nowhere |
| June | Świnoujście | 18.1°C | nowhere |
| July | Kronstadt | 20.6°C | 13 of 90 |
| August | Świnoujście | 20.3°C | 34 of 90 |
| September | Gdańsk | 17.9°C | nowhere |
| October | Palanga | 14.1°C | nowhere |
| November | Palanga | 10.8°C | nowhere |
| December | Rønne | 7.0°C | nowhere |
"Comfortable" means at least 19.0°C, which is a judgement and not a fact — a Norwegian and a Spaniard genuinely disagree. Every city page shows the season at four thresholds instead of insisting on one. Method and sources