[QUOTE=pmeunier;3224782]I remember reading some studies that said dry mucous membranes (sinuses) makes one more vulnerable to infection. It's not hard to find similar statements from relatively trustworthy sources:
"The most common cold-causing viruses survive better when humidity is low -- the colder months of the year. Cold weather also may make the nasal passages' lining drier and more vulnerable to viral infection. "
That sir is correct