Enchanted snow is a magical imitation of snow. It shares most of the properties of snow (density, colour, shape etc.), however, unlike snow, it is warm and dry. It is usually used as a decoration around Christmas in the wizarding world, probably in the same way Muggles use tinsel or baubles.
Enchanted snow fell from the Great Hall's enchanted ceiling in the Christmas of 1992.
12 Grimmauld Place was covered in heaps of Enchanted Snow in the Christmas of 1995.
The Christmas tree at the reception area in St Mungo's Hospital for Magical Maladies and Injuries was decorated with enchanted snow.