The Coriolis force and wind patterns
The Coriolis Effect can cause cyclic wind patterns on Earth.
SourceThe earth’s rotation about its axis means that it is not
perfectly inertial. Though generally small,
the associated effects do
have a significant impact on large-scale motion across the earth’s surface–
in particular on wind patterns. As air is driven down a pressure gradient it
is deflected by the Coriolis force to form circular paths centred on the
high-pressure region. The paths have a different sense in the northern and
southern hemispheres (clockwise above the equator,
anticlockwise below). A similar effect is supposed to be evident in the
path followed by the water in your bath, as it drains away
(remember
this picture?). But this is rather doubtful,
as you will find
on this debunking page.