Right now, I'm doing some research on Arctic climates for material development (more on that to come). I found this great NASA site on the ozone hole over Antarctica (FYI, ozone is a colorless gas which absorbs UV-B rays from the sun, and thus protects the environment below).
Usually, NASA sites can be too dense with information/graphs/tables/etc, but this is a really clean site with Tufte-esque infographics, daily updated pics of the ozone hole, and animation over months/years. There's also a nice explanation of how the units they use to measure the amount of ozone (dobson unit).
In the Arctic, spring occurs roughly from Sept-Dec, so the ozone hole gets quite a bit larger during this time (meaning that the ozone concentration gets smaller).