Cold weather itself makes you catch a cold

What we know

The common cold is caused by any of over 200 different viruses, most commonly rhinoviruses, that infect the upper respiratory tract, and infection requires exposure to the virus itself through respiratory droplets, contaminated surfaces, or direct contact, not simply exposure to low ambient temperature. Being cold, wet, or underdressed in winter weather does not, by itself, cause a viral infection to develop in the absence of actual exposure to a cold-causing virus, a point virologists have made consistently when addressing this widespread belief, including in published reviews examining historical and modern experimental attempts to test the claim directly.

Several controlled experiments dating back decades have specifically tested whether cold exposure alone causes colds. A frequently cited study from the Common Cold Unit in the United Kingdom during the 1960s and 1970s deliberately exposed volunteers to cold conditions, including having some subjects sit in cold rooms or take cold baths, while controlling for actual viral exposure, and found that cold exposure alone, without virus exposure, did not produce cold symptoms, directly testing and failing to confirm the folk belief in a controlled setting. This body of research established the foundational point that a virus must actually be present for infection to occur, regardless of ambient temperature.

What complicates the simple 'false' verdict, and explains why colds and flu remain strongly and reliably seasonal even though cold air itself is not the direct cause, is a set of genuine biological and behavioral mechanisms linking colder weather to increased transmission. Laboratory research published in the Proceedings of the National Academy of Sciences found that colder, drier air conditions extend the survival time and airborne transmissibility of certain respiratory viruses, including influenza, outside the body, meaning viral particles may remain infectious longer in winter conditions than in warm, humid summer air. Separately, some research suggests cold temperatures may cause modest, measurable reductions in the immune responsiveness of nasal passage tissue, an effect studied in a 2015 Yale University research team's findings on temperature-dependent innate immune response in nasal cells, potentially making the body somewhat less effective at clearing an early-stage viral infection in cold conditions, though this remains an area of ongoing research rather than settled, definitive mechanism.

Behavioral factors linked to cold weather are also well documented contributors to the seasonal pattern: people spend more time indoors in enclosed, poorly ventilated spaces during cold months, increasing close contact and shared air with infected individuals, schools and workplaces cluster people together during exactly the months when respiratory viruses circulate most, and reduced ventilation in winter, when windows are kept closed for warmth, allows viral particles to accumulate indoors rather than dispersing as they would outdoors or in well-ventilated conditions. Public health researchers studying seasonal respiratory illness patterns consistently point to this combination of factors, viral survival advantages in cold dry air, indoor crowding, and possibly modest immune effects, rather than cold exposure alone, as the actual explanation for winter's higher cold and flu rates.

The folk belief likely persists because the seasonal correlation between cold weather and cold illness is genuinely strong and easy to observe, making the causal leap to 'cold weather causes colds' feel intuitively obvious even though the actual causal chain runs through virus survival and human behavior patterns rather than through temperature exposure acting directly on the body to produce infection.

Common claims

• Going outside in cold weather without a coat will give you a cold.False, cold exposure alone without viral exposure does not cause a cold, as shown in controlled studies.
• Colds and flu really are more common in winter.True, but this is explained by viral survival in cold dry air and increased indoor crowding, not cold exposure itself.
• Cold air may reduce the nose's immune defenses somewhat.Partly supported, some research suggests a modest effect, though this remains an active area of study.
• Wet hair or damp clothing in cold weather causes colds directly.False, this is a specific version of the myth not supported by controlled experimental evidence.

Evidence hierarchy

All sources

• Why do we get more colds in winter?Harvard Health Publishing · 2022
• Absolute humidity and the seasonal onset of influenza in the continental United StatesPLOS Biology · 2010
• Rhinovirus replication and innate immune response at cooler temperaturesProceedings of the National Academy of Sciences · 2015
• Common coldNHS · 2023

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