Abstract
Based on 16 years of oceanographic and meteorological data the monthly variations of the net heat flux at the air-sea interface in coastal waters near Jeddah show that the sea gains an average of about 14 plus or minus 2 W/m super(2) from April to October and loses about 79 plus or minus 4 W/m super(2) from November to March. The loss of heat during the winter months is not compensated by the gain during the summer months and therefore leads to an annual average deficit of 25 plus or minus 3 W/m super(2). The gain during summer may not favour the formation of a strong seasonal thermocline.