The popular but contested notion that people are more likely to catch a cold in cool weather appears to be grounded in physiology.
It is already known that most strains of rhinovirus (RV) — the common cold virus — replicate better at the cooler temperatures found in the nasal cavity (33–35 degrees Celsius) than at core body temperature (37 degrees Celsius). Now, a study in mice has shown that the strength of antiviral immune response in infected cells also varies according to temperature, being strongest at higher temperatures and diminished at lower temperatures.
“These findings compel further investigation of how host responses to infection affect the temperature range permissive for RV replication and thereby impact the pathogenesis of RV-associated diseases,” write Ellen Foxman and co-authors in Proceedings of the National Academy of Sciences of the United States of America (online, 5 January 2015)
 Foxman EF, Storer JA, Fitzgerald ME et al. Temperature-dependent innate defense against the common cold virus limits viral replication at warm temperature in mouse airway cells. Proceedings of the National Academy of Sciences of the United States of America. 2015. doi:10.1073/pnas.1411030112.