Does Cold Weather Cause the Common Cold? The Viral Truth
False. The common cold is caused by viruses — primarily rhinoviruses — not by cold temperatures. You cannot catch a cold from being cold. The correlation between winter and cold prevalence is real but explained by increased indoor crowding, lower humidity enabling viral transmission, and in the case of rhinoviruses, optimal replication temperature in the cooler nasal passages.
"Cold Weather Causes the Common Cold" is a myth. The scientific consensus is clear, the primary sources are documented above, and the exact origin of the false belief can be traced. Read on for the full evidence.
"Cold Weather Causes the Common Cold"
False.
Go outside with wet hair and you'll catch a cold. Put on a coat or you'll get sick. The belief that cold or wet conditions cause the common cold is one of the most universally held folk medicine beliefs, maintained by parents across generations with complete confidence. It is wrong. Colds are caused by viruses — you cannot get a cold without being exposed to a cold virus, regardless of how cold or wet you get. The correlation between winter and increased cold rates is real, but the mechanism is viral transmission, not temperature.
What Actually Causes Colds
The common cold is caused by viral infection, primarily rhinoviruses (responsible for approximately 30–50 percent of colds), but also coronaviruses (not SARS-CoV-2 variants, but endemic seasonal strains), adenoviruses, respiratory syncytial virus (RSV), and parainfluenza viruses. These viruses infect the mucous membranes of the upper respiratory tract — nose, throat, and sinuses — and trigger the immune response that produces familiar symptoms: runny nose, sore throat, sneezing, and fatigue. Transmission occurs through direct contact with infected respiratory secretions — via droplets expelled during sneezing or coughing, or via hand-to-face transmission after touching contaminated surfaces. To get a cold, you must be exposed to a sufficient quantity of cold virus and the virus must successfully establish an infection in your upper respiratory tract. Cold temperatures alone, wet clothing, damp hair, or drafts cannot cause viral infection because these conditions introduce no virus.
The Classic Cold-Weather Experiments
The causal relationship between temperature and colds has been tested experimentally. In studies conducted at the Common Cold Research Unit in Salisbury, England, during the 1950s and 1960s (run by Sir Christopher Andrewes and colleagues), volunteers were exposed to cold viruses in controlled conditions — some in warm environments, some in cold environments, some after being soaked in cold water. The results were consistent: cold exposure alone, in the absence of virus exposure, did not cause colds. Subjects exposed to cold virus developed colds at similar rates regardless of temperature or wet conditions. A 2005 study by Johnson and Eccles in Family Practice had volunteers submerge their feet in cold water for 20 minutes, then compared cold incidence over five days with a control group. The chilled group did develop significantly more colds — but the authors proposed this was because chilling caused vasoconstriction in the nasal passages, potentially reducing local immunity and enabling viral infection in people who were already sub-clinically exposed to cold virus. The chilling did not create viral infection from nothing.
Why Colds Are More Common in Winter
The winter cold season is a real phenomenon that requires explanation if temperature is not the cause. Several mechanisms operate. First, indoor crowding: in cold weather, people spend more time indoors in close proximity, creating more opportunities for viral transmission. Second, lower humidity: cold air holds less moisture, and the dry heated air of winter interiors is less humid than summer air. Respiratory droplets (the primary vehicle for cold virus transmission) evaporate more rapidly in dry air, releasing smaller, longer-airborne viral particles that linger in the air longer. Research has confirmed that rhinovirus transmission rates are higher at low humidity. Third, rhinovirus biology: rhinoviruses replicate optimally at approximately 33–35°C — lower than core body temperature but the temperature of the nasal passages in cold air. When you breathe cold air, your nasal passages cool slightly, creating more optimal conditions for rhinovirus replication if already exposed. Fourth, vitamin D: sunlight exposure decreases in winter, potentially reducing vitamin D synthesis, which plays a role in immune function. Each of these factors contributes to winter cold seasonality without cold temperatures being directly causal.
The Verdict
Cold weather does not cause the common cold. Colds are caused by viral infection, and you cannot get a cold without viral exposure. Cold temperatures correlate with increased cold incidence in winter because of indirect mechanisms: indoor crowding, lower humidity facilitating viral transmission, and nasal cooling that may favour rhinovirus replication. The experimental evidence is clear: cold exposure alone, in isolation from viral exposure, does not produce colds. Going outside with wet hair in winter does not cause a cold. Exposure to someone with a cold does.
Does Being Cold Weaken Your Immune System?
The question of whether cold exposure affects immune function is more nuanced than simple cause-and-effect. The 2005 Johnson and Eccles study suggested that cold-induced vasoconstriction in the nasal passages might reduce local immune defences, potentially enabling subclinical viral exposures to become symptomatic infections. A small number of studies have examined the effect of acute cold stress on various immune markers, with inconsistent results — some showing transient changes in certain immune parameters, others finding no effect. The broader literature on cold water immersion and immune function, extensively studied in athletes, similarly shows transient changes without clear clinical significance. The immune system is a complex distributed network not significantly compromised by brief cold exposure in healthy people. Whatever modest effect cold exposure may have on nasal immune function, it is orders of magnitude less important than viral exposure as a determinant of whether you develop a cold. The practical message remains: avoiding infected people and washing hands are the evidence-based cold prevention strategies, not avoiding cold weather.
Primary Sources
- [1] Eccles, R. (2002). An explanation for the seasonality of acute upper respiratory tract viral infections. Acta Oto-Laryngologica. ↗ Source
- [2] Johnson, C. & Eccles, R. (2005). Acute cooling of the feet and the onset of common cold symptoms. Family Practice. ↗ Source
- [3] Makinen, T. M. et al. (2009). Cold temperature and low humidity are associated with increased occurrence of respiratory tract infections. Respiratory Medicine. ↗ Source
Frequently Asked Questions
Does cold weather cause the common cold?
No. Colds are caused by viruses, primarily rhinoviruses. You cannot catch a cold from cold temperatures alone — you need viral exposure. Cold weather correlates with more colds because of indoor crowding, lower humidity, and other indirect factors that promote viral transmission.
Can you get a cold from going outside with wet hair?
No. Wet hair or cold exposure without viral contact cannot cause a cold. The virus must be present. Wet hair might make you uncomfortable, but discomfort alone does not cause viral infection.
Why are colds more common in winter?
Multiple factors: people spend more time indoors in close proximity (facilitating transmission), cold air is less humid (droplets evaporate faster, releasing smaller airborne viral particles), and nasal passages cool slightly in cold air (creating optimal rhinovirus replication conditions).
What viruses cause the common cold?
Rhinoviruses (30–50%), coronaviruses (not COVID-19 variants — endemic seasonal strains), adenoviruses, RSV, and parainfluenza viruses. Over 200 viral strains can cause cold symptoms.
Does being cold weaken your immune system?
Cold exposure may cause minor, transient changes in some immune parameters, but healthy people's immune systems are not significantly compromised by brief cold exposure. Viral exposure is far more important than cold temperature as a determinant of getting sick.
How do colds actually spread?
Through respiratory droplets when an infected person sneezes or coughs, and through hand-to-face transmission after touching contaminated surfaces. Hand washing and avoiding close contact with infected people are the most effective prevention strategies.
Why do people believe cold weather causes colds?
Because the correlation is real — more colds happen in cold weather. The mistake is inferring that cold temperatures are the cause rather than the context for other factors (crowding, humidity) that genuinely drive transmission.
How We Verified This Claim
SmartAss Facts evaluates every popular belief against a three-tier source hierarchy: primary sources (peer-reviewed research, government datasets, and court records), secondary sources (reputable journalism citing the primary), and tertiary sources (blogs and general reference sites). Only primary sources are cited. If a claim can only be traced to a blog or an unsourced assertion, it is not used.
For this myth — Cold Weather Causes the Common Cold — we reviewed the cited primary sources above, cross-referenced against independent scientific literature, and confirmed the verdict with the consensus position of relevant professional bodies (including the sources listed). The claim was then fact-checked against the SmartAss Facts database of over 5,000 verified facts to identify related content.
If you believe our verdict is incorrect or you have a more recent primary source that changes the analysis, the science always wins — we revise pages when the evidence warrants it. Last reviewed: 2026-05-23.
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