Imagine that you are combing a tennis ball which is hairy rather than fluffy. You attempt to comb it so that all the hairs are lying flat on the surface and so that they change direction smoothly over the whole surface, but the Hairy Ball Theorem says that you will fail.
Since the earth is a ball, and the wind at any point has a direction, as if
the air were being combed over the Earth's surface, it follows that there is
always a cyclone somewhere.