When the earth receives solar radiation, a large fraction of this incident radiation is usually absorbed by the oceans and the seas, which become warm. Usually, equitorial regions are the ones that have this phenomenon. Now, when ocean currents are flowing from the equator, they usually carry this warm water with them thereby moving the greatest amount of heat from the equator on its way out.
For example, In the Pacific Ocean, there is a current known as Alaska Current that carries warm water in the northward direction thereby making Anchorage which is Alaska's largest city to have a much mild weather than the inland areas with the same latitude.
