The time delay Δ between the warmest day in the mean annual curve and 21 June varies from 55 days over the coastal sea to 35 days in the inland of the Netherlands. Worldwide the lowest values is about 25 days for remote continental areas (Siberia). The delay seawater is about 60-65 days. The major variation is found in a coastal zone of 50 km lateral extend.  The variation is understood by a simple model of periodic sinusoidal heating and Newtonial damping.