This animation showes the snow cover over the month of Feb from 2001 to 2019. The snow covers different places in the world. Most of the snow is up north and in antarctica. Some places get more snow than others. Like most Northern countrys they have snow but countrys that are near or on the equater don't have any.
This key is showing the percent of snow that is covering. The lightest color is showing that it is fully covered. And the darkest is only partly covered.