While the ozone hole reached 27 million km2 in 2008 (red line on the diagram), against 25 million km2 the year before ‘in blue), it was still under the 29 million km2 recorded in 2006 (in green).
Because of the ODS (ozone depleting substances) phase-out mandated by the Montreal Protocol, their stratospheric concentration has started to decrease, starting ozone layer recovery. However, due to their atmospheric lifetime, it will still take decades before the ozone hole vanishes.
In the meantime, cold temperatures over the pole are the most important factor in the fluctuation of the size of the ozone hole from year-to-year.
The hole typically reaches its maximum extent in September or early October, and then dissipates in November.