Water temperature in Poland

Poland's Baltic coast in summer

Poland swims in the Baltic, whose coastline stretches with wide sandy beaches from West Pomerania to the Gulf of Gdańsk, where the Hel Peninsula separates the sheltered bay from the open sea. The Baltic warms slowly through June and usually peaks in July and August, with sheltered bays warming earlier than the open coast. Inland, numerous lakes, for example in Masuria, grow warmer than the sea in high summer.

The 10 coastal sites come from two sources. For most places, temperatures come from the Open-Meteo marine model and carry a model label in the app. Two sites provide measured values from buoys or stations distributed by the Copernicus Marine Service. Lakes and rivers are not yet part of this dataset. Bathing sites are officially tested independently of these temperature sources.

The State Sanitary Inspectorate tests bathing waters during the season, with ratings from excellent to poor under the EU Bathing Water Directive. In high summer, cyanobacteria blooms can spread in the Gulf of Gdańsk and elsewhere, and bathing sites are then closed temporarily. Offshore wind can bring cold deep water to the surface along the coast, dropping the temperature overnight. During the season, lifeguarded beaches use flags to show whether swimming is allowed.