Winter White Dwarfs change their coat with decreasing light (autumn) and increasing light (spring). NOT with a change
in temperature. DO NOT put your hamster into the refrigerator or freezer to make them change. It will kill them. The
change happens with the molt occurring during the change in amount of daylight. Not all Winter White Dwarfs will change
their coats with the seasons and not all go through a complete change to white. The last picture is as light as this girl
went. I will add pictures of the reverse process when I get them.
Hybrid Dwarfs (Winter White Dwarfs crossed with Campbells Dwarfs) may or may not change coats, too.
It is rumored that while in the winter coat they are won't breed and are infertile. What happens is they go into heat
less often and are less fertile. They can and do breed in their winter coats but produce fewer litters that are smaller
then normal. I have had this happen to me personally.