The influence of cold currents is mostly felt in the middle latitudes in winter higher latitudes in winter higher latitudes in spring tropics all year long

The influence of cold currents is mostly felt in the tropics. 
Ocean currents act much like a conveyor belt, transporting warm water and precipitation from the equator toward the poles and cold water from the poles back to the tropics. Currents therefore regulate global climate, helping to counteract the uneven distribution of solar radiation reaching Earth's surface. 

movement of energy through space or a medium Hope this works! ;3