Cold weather causes the common cold
The common cold is caused by viruses, primarily rhinoviruses, and cold temperatures alone cannot cause infection. The higher prevalence of colds in winter is explained by increased indoor crowding and closer contact with infected individuals, not by exposure to cold air itself.
What we know
The common cold is caused by over 200 different viruses, with rhinoviruses responsible for the majority of cases. Infection requires exposure to one of these viruses, typically through respiratory droplets or hand-to-face contact. Cold air itself has no ability to initiate a viral infection.
Controlled experiments exposing volunteers to cold temperatures have not shown increased rates of colds compared to those kept warm. The seasonal pattern of colds in winter is better explained by behavioral factors: people spend more time indoors in close proximity to others, facilitating viral transmission. Some research also suggests that rhinoviruses may replicate more efficiently in the cooler temperatures of the nasal cavity in winter, though this is a different mechanism from simply being cold.
Going outside with wet hair or without a coat in winter does not cause colds. If a person gets sick after being cold and wet, it is because they were already exposed to a virus, not because of the temperature. Low humidity in winter may also dry out nasal passages, potentially making them slightly more susceptible to viral entry, but this is a minor contributing factor rather than a direct cause.
Experts from the Mayo Clinic, University of Utah Health, and other institutions consistently state that cold weather does not directly cause colds. Effective prevention focuses on hand hygiene, avoiding contact with sick individuals, and not touching the face.
Common claims
- Going out in the cold without a coat gives you a coldNo evidence; viruses cause colds
- Wet hair in winter makes you sickNot supported by evidence
- Cold temperatures directly weaken your immune systemNot established for mild cold exposure
- Staying warm prevents colds in winterOnly indirectly, via less crowding
Evidence hierarchy
All sources
- Can cold weather cause a cold? - Mayo Clinic MinuteMayo Clinic News Network · 2024
- Does cold weather make you sick? Experts explainUniversity of Utah Health · 2026
- Can cold weather get you sick?GoodRx · 2022
- University of Rochester: Myth masher - cracking the case on coldsUniversity of Rochester Medicine · 2026