Does cold weather actually make you sick?

The straightforward correction is that you cannot catch a cold from being cold, since colds are caused by viruses, principally rhinoviruses, and no amount of chill produces one in the absence of infection. That has been the standard public health message for decades, and it is right about the fundamental point. But the folk wisdom turns out to have more behind it than the flat debunking allowed.

A 2022 study found a genuine mechanism: cells lining the nose release extracellular vesicles that swarm and neutralize inhaled viruses, and dropping nasal temperature by just a few degrees, as happens in cold air, cut that protective response substantially. Cold, dry air also impairs the mucus clearance that sweeps pathogens out, and low humidity helps some viruses survive longer in the air. Layer on the behavioral factors, people crowding indoors with less ventilation, children returning to school, and less sunlight reducing vitamin D, and winter's seasonal pattern makes sense as a combination of impaired defense, better viral survival, and more exposure. So the accurate version is that cold weather does not cause illness but does plausibly increase susceptibility and transmission, which is a more interesting answer than either the myth or the standard correction.