The Rutgers Snow Extent Climate Data Record gives a time series of snow cover the Northern Hemisphere. Also broken down into major landmasses.
It's a product of Rutgers University Global Snow Lab
Other data products are available, such as weekly time series and time series for individual landmasses, and snow cover images.
Rutgers Snow Extent Climate Data Record. No author.
Retrieved 06:30, May 24, 2013 (UTC).
the Data Hub