The oceanographic observation (oceanObs) API service contains oceanographic observation data, e.g. water level and water temperature, from stations located in Denmark. You can read more about oceanographic observations and how they are attained under data information.
If you want to download large quantities of historical oceanographic observation data, we recommend that you use DMI’s bulk download service. The service lets you download .zip files, each containing historical data for a month going back to 1889. You can also download all historical data by selecting the file all.zip.