Compared to warm winters, cold winters are likelier to land more people in the hospital, particularly the emergency room. 
A colder temperature slows down a viral-infected cell's ability to commit suicide.
The cranial sinuses are eight cavities within the skull that supply vocal resonance. When they become inflamed, often accompanied by facial pain, fever, and nasal congestion, the condition is called sinusitis. Sinusitis will affect one in eight American adults in their lifetime, and can be caused by an infection from a virus (most commonly), bacteria, or fungus; it can also be the result of an allergic reaction.