Weather: Dry or hot weather can cause a dog's nose to dry out. Just like human skin, a dog's nose can be affected by environmental conditions.
Allergies: Allergic reactions can lead to nasal dryness in dogs. Pollen, dust, or other allergens may irritate the nasal passages.
Dehydration: If a dog is not drinking enough water, it can lead to dehydration, which may manifest as a dry nose among other symptoms.
Age: As dogs age, their noses may naturally become drier. This is a normal part of the aging process.
Medical Conditions: Autoimmune disorders and infections can modify a dog's nasal moisture. If you suspect a problem, see a vet for diagnosis and treatment.