Here we go, Frink:

The Ozone "hole" is caused by the Polar Vortices which occur at the poles, obviously. The one at the North Pole isn't strong enough to carry CFCs and other chlorine atoms up to the stratosphere. The South Polar Vortex is far stronger, and longer lasting, but still only occurs between the months of August and November, in normal cases.

Source (specifically the second and third sections):

http://ozonewatch.gsfc.nasa.gov/facts/vortex_NH.html

Here is a source that describes the ideal situation for ozone destruction created by the Polar Vortex (particularly the section called "The Ozone Hole"):

http://chemwiki.ucdavis.edu/Physical_Chemistry/Kinetics/Case_Studies%3A_Kinetics/Depletion_of_the_Ozone_Layer

The following graph charts ozone depletion throughout the year. As you can see, it occurs from August to November before stabilizing again, rather than continuing to drop over the years.

The Polar Vortex pushes ozone away from it, as well as carrying chlorine particles into the stratosphere. This decreases the concentration of ozone over the South Pole even more than chlorine atoms do, as well as creating a greater concentration of ozone outside the Polar Vortex:

So the ozone hole is limited to Antarctica, and to a far lesser extent, the Arctic.