Monthly mean (average of weekly analyses associated with respective month) of sea-surface temperature in the North Sea as spatial mean over grid-cells of the coarse resolution analysis grid based on a Lambert azimuthal equal-area projection with center point at 56°N, 4°E and a spatial resolution of 20 nautical miles (24x30 grid cells with corner grid-points at 60,81°N, -5,31°E; 60,81°N, 10,36°E; 51,17°N, -2,13°E; 51,17°N, 10,06°E); base data is the weekly SST-analysis performed in division M21 at BSH, that is a manual analysis based on in-situ observations for the period 1968-1994, that has been digitized, as well as the "blended SST-analysis", that is a product combining in-situ observations and satellite retrievals from 1995 onwards