I have noticed this with Annie as well. She does have allergies so that explains the sometimes runny nose...also there have been times I thought it was a runny nose but turned out she had just been snorkeling in the water dish 
Completely normal "a cold wet nose " - healthy dog is the myth,It changes from dry to wet and then back.
The temperature and moisture of your dog's nose are not miracle measurements of his health. For instance, a dog's nose is often dry and/or warm if he has just woken up, and this is perfectly normal. However, a nose that is persistently dry and crusted might be a sign of a health problem.