The annual nariation of surface heat exchange at ten selected station in the Korean coastal seas was studied using data of monthly mean surface temperature and meteorological parameters averaged for many years. Through heat exchange between the sea and the atmosphere, the surfaces in the Korean coastal seas are warmed by accepting heat from the atmosphere during march to September in the west coast sea, during Aprill to August in the south coast sea which includes the Ulleung-do coast sea and during April to September in the east coast sea. The periods which are cooled by losing heat to the atmosphere correspond to residual months excepting the above warming periods. Maximum total heat exchange during the warming period at each station shows the distribution of 320-720cal/ $ extrm{cm}^2$ day in June to July and during the cooling period shows the distribution of -260∼-940 cal/$ extrm{cm}^2$ day in November to January. The annual average total heat exchange shows warming of 100-240 Cal/$ extrm{cm}^2$ day in the west coast sea, cooling of -90∼-150 Cal/$ extrm{cm}^2$ day in the south coast sea and the Ulleung-do coast sea, and slight warming or cooling of -15∼65 Cal/$ extrm{cm}^2$ day in the east coast sea. Maxima or minima of the surface temperature in the Korean coastal seas appear in the month that the warming or cooling period is ended. The evaporation rate is highest during October to next January with the distribution of 5∼12mm/day.