Chilled Air Doesn't Cause Colds, Science Confirms

Is going outside in the cold what makes you sick? The answer is no. Colds and other respiratory infections are more common in winter. However, scientists say this is correlation, not causation. The chilly weather itself is not the direct cause. "The main driver is behavioural," explains Professor John Tregoning, a vaccine immunology expert at Imperial College London. In colder months, people spend more time indoors. This means closer contact with others and often poorer ventilation, which helps viruses spread. There is one minor environmental factor. In summer, sunlight contains UV light that can deactivate viruses. Droplets from a sneeze also evaporate faster outdoors. But this effect is small. The key takeaway: you catch a cold from a virus, not from the cold air. The seasonal increase is due to human behavior, not the temperature.