The size of the ozone hole fluctuates – usually forming each year in August, with its peak in October, before finally closing in late November or December. Not only will the hole close earlier than usual in 2019, but it is also the smallest it has been in 30 years owing to unusual atmospheric conditions.

Forecasts from the Copernicus Atmosphere Monitoring Service (CAMS), which uses total ozone measurements from the Copernicus Sentinel-5P mission processed at the German Aerospace Center, have forecasted that this year's ozone hole will close sooner than usual.