Decreased solar irradiance during the summer months near the coast of southern California is related to coastal upwelling. It is calculated that if monthly averages of percent of possible sunshine were the same in June as they are in January, the sea surface would receive 37 Ly/d more than it ordinarily receives. Consequently, the sea surface temperature is 1.1¿C cooler in June than it would have been otherwise. Patterns of salinity, air temperature, and dew point temperature for the period 1950--1972 are also discussed.