To firstly answer this question, you must know what the Coriolis effect is. In simple terms, it can be defined as something that causes displacement - making things move at a curve, rather than a straight line. This aforementioned effect applies to winds within the hemispheres. Here's how this effect messes with the winds.
Winds move in a counterclockwise direction in the Northern Hemisphere and in a clockwise direction in the S. Hemisphere.