Many dog owners have heard the saying that a cold nose means a healthy pup, but this idea oversimplifies the complex nature of canine health. A dog's nose temperature can fluctuate due to a variety of factors, including the environment and the dog's activity level. For instance, a dog that has just come in from a chilly walk may have a cooler nose, but that doesn't necessarily mean they are healthy or unhealthy. Similarly, a warm nose could indicate illness, but it could also simply be normal warmth after resting in a cozy spot.