The correlation of global ocean surface temperatures with ocean heat content at interannual to decadal time scales shows wind-driven ocean circulation plays a fundamental role in the Earth’s energy balance. Wind-driven baroclinic Rossby waves contribute to the adjustment of the ocean circulation to the winds modulating ocean heat content at mid-latitudes. Here we use observational records, a reanalysis and a Rossby wave model to quantify the contribution of the waves to the variations in air-sea heat flux. We find that Rossby waves crossing the South Pacific at 35ºS can explain up to 70% of the interannual variance of the heat flux. The heat exchange attributed to the waves, ranging from -9 to 21 W m^-2, has contributed to the multi-year increase in heat in the central Pacific. Heat fluxes due to Rossby waves could be forecast to provide predictability of this component of the heat exchange with the atmosphere.