What causes the color of a dog’s nose to fade in winter?
-Lack of sunlight from staying inside
Insufficient amounts of vitamin D
-Excessive loss of heat through the nose
-There is no definitive reason why this happens
If a dog’s nose becomes anything other than the cold, wet nose normal for the species, an evaluation is in order. It could be nothing more than “winter nose,” a benign condition also called “snow nose.” This condition affects many breeds, from Labradors to terriers. A normally black nose may fade to a lighter shade of brown, or even pink, in the cold of winter. The dark pigment usually returns as the weather warms up. There is no definitive explanation for why this happens. Source: AKC.org