To have snow on the ground in all 50 states at the same time, is a fairly rare feat. The last time all 50 states had snowfall on the ground at the same time was on February 12th, 2010.
A little known fact about Hawaii is that it often snows. Of course, that is always on the Big Island's Mauna Kea volcanic peak. Typically, the hardest state to get accumulating snowfall is Florida. This season has already featured three snowfall events in northern Florida!