Water temperature in Denmark

Denmark's coasts, fjords and belts

Denmark is surrounded by sea. To the west lies Jutland's exposed North Sea coast, to the east the calmer Baltic with the Kattegat, the Øresund and the Belts. Fjords such as the Limfjord, Isefjord, Roskilde Fjord and Randers Fjord reach deep inland. Sheltered fjords and shallow bays warm earlier in summer than the open coast, while the North Sea stays fresher and more changeable. The sea usually peaks in August, and the swimming season is centred on June to August.

The 50 sites come from two sources. The Danish Meteorological Institute, DMI, measures water temperature continuously at coastal stations, and these values are measured. For other coastal places, temperatures come from the Open-Meteo marine model and carry a model label in the app. Lakes are not yet part of this dataset. Official bathing sites are tested by the municipalities independently of these temperature sources.

Municipalities test bathing sites during the season, with ratings from excellent to poor under the EU Bathing Water Directive. On the North Sea coast, dangerous rip currents form near groynes and sandbanks, so warning signs and flags deserve attention. Offshore wind can also carry swimmers and inflatables out to sea. Lion's mane jellyfish turn up from time to time in the Kattegat and the Baltic in high summer, and water quality at some sites can dip briefly after heavy rain.