The Coriolis effect causes global wind currents to blow in a diagonal direction due to the rotation of the Earth. If the Earth didn't rotate, wind currents would blow straight north and south from the poles to the equator due to the pressure differences between the two regions.
However, as the Earth spins, the Coriolis effect causes a slight change in these north-south winds that influences their direction. These effects are not the same for the northern and southern hemispheres because each hemisphere has its own trade wind patterns that blow from its respective pole to the equator and back. This means that the Coriolis effect causes the winds in the northern hemisphere to shift to the right, while the wind currents in the southern hemisphere shift towards the left.
This happens because the earth is rotating underneath the wind current in a very fast counterclockwise direction, leading to this perceived shift in the current. However, the wind currents themselves are not actually shifting; it simply looks as if they are due to the earth rotating below them.
Virtually all weather systems and wind currents move in this same way with the only exception being low-pressure systems. In this type of system, the force of the pressure gradient cancels out the Coriolis effect, and these winds blow in reverse.