Judging your dogs health off of their nose is not always the best bet. As a dog gets older they start to do have a drier nose, so this is not always a cause for concern. If the dog is showing other symptoms along with a overly wet or dry nose then you should always take them to the vet.
There are quite a few wives tales about why dogs have wet noses but here are a few actual reasons, explained:
Housekeeping: A dog’s nose gets into everyone’s business, not to mention his food dish. He constantly licks his nose to keep it clean, leaving it cool and wet.
A dog is covered with hair, and is unable to sweat through the skin like a person does. Instead, dogs dissipate body heat through their mouths, by panting, and through their wet noses, by evaporation. Special mucous glands inside the dog’s nostrils produce the clear watery fluid that helps speed the cooling process.
Now if your dogs cold or warm wet nose is accompanied by swelling, sores, cuts discharge or anything that looks out of the ordinary, take them to the vet. Do you notice when your dogs nose is always wet and when it is dry?