In Europe, areas with a mean temperature at or below -3°C (26.6°F) are the areas that retain a snowpack.
It’s not that cold here, outside of maybe higher elevations north and west of the city, the city itself has a mean temp of roughly 2°C for the winter. We’re also at a more southerly latitude than the vast majority of Europe, which means longer winter days and stronger sunshine. Mean temperatures colder than -3°C may actually be required to retain a real snowpack in eastern North America, for the aforementioned reasons.
In Japan, locations with the same average temperatures as here receive significantly more snowfall than we do. Although their snow is drier than ours typically is, I’d imagine it’s enough retain a snowpack.