Many people across cultures grow up hearing that cold weather makes you sick. Going outside without a coat, breathing in cold air, sleeping in a chilly room, getting caught in cold rain or snow, or simply feeling chilled are often blamed for causing colds or flu.

This belief feels true to many people because illness often follows cold exposure. However, modern research shows that the connection between cold weather and illness is more nuanced than the idea that cold directly causes disease.

Cold temperatures themselves do not cause infections. Instead, they influence a combination of biological, environmental and social factors that make people more vulnerable to respiratory illnesses, especially during the winter months.

Colds and flu are caused by viruses, not by cold air. Viruses such as rhinoviruses, which cause the common cold, and influenza viruses spread from person to person through respiratory droplets or physical contact, regardless of the temperature outside. That said, rates of respiratory infections consistently increase during colder seasons in many parts of the world – a pattern that has been observed globally.

Read more: Do I have to wear a jacket when it's cold outside?

This seasonal pattern is partly due to the way that cold temperatures and low humidity affect viruses in the environment. Research shows that many respiratory viruses, including influenza viruses and........

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