There you are admiring your beautiful dog, and you noticed that your dog's nose has changed color from black to lighter browns or even pink. What's going on! Your dog probably has a temporary — and harmless — case of "winter nose," or, as it's often called, "snow nose." Sometimes, when the temperature drops and seasons change, an enzyme called tyrosinase which makes melanin also drops. When this happens, it will cause a dark nose to lighten or even become speckled with pink.
Some breeds are more prone to snow nose (aka nasal depigmentation) like Siberian huskies, Bernese Mountain Dogs, Labrador retrievers, and Golden retrievers are the most common breeds to have this cosmetic condition, that poses no medical threat.
Sometimes an injury or sunburn could turn your dog's nose lighter, but you would notice blistering from sunburn or some evidence of an injury if that were the case well before the color changed.
In some unusual cases, changes in pigment could indicate the autoimmune disease, vitiligo. If you have questioned whether your dog has snow nose or vitiligo, make an appointment to see your veterinarian.
With your dog's nose color change, and taking the winter season into account, your dog's nose should return to normal color once the warm weather returns.