This is a more complicated question than it seems.
I lived in Maine. We had snow cover for many months in a row.
If you ask, "Is it snowing?" you mean "Right now, are there snow flake falling from the sky?"
That's not the same as "Is there snow on the ground right now?" The idiomatic way to ask about that can vary. "Do you guys have snow yet?" (late October) "Do you still have snow?" (late March)
As a side note, there is little use about asking "in the USA" since at any given time, there is snow on the ground in Alaska and not in Hawaii.