Coriolis force is an apparent force caused by the Earth’s rotation. It is
responsible for deflecting winds towards the right in the northern hemisphere
and towards the left in the southern hemisphere.
Under the effect of coriolis force, the trade winds moving from sub-tropical
high pressure belts to equational low pressure belts become north-east
trade winds in the northern hemisphere and south-east trade winds in the
southern hemisphere. As a result, they bring heavy rainfall to the east coast
and the west coast remains dry.