Catching a chill after a long day out in the low temperatures does not lead to a cold. Colds are caused by viruses. Caveat: If you have gotten really cold it can depress your immune system and if you’re exposed to a cold virus at this time, you might catch it more easily. When going outside this time of year, dress in layers, choosing natural fabrics or those designed for athletic use, to keep yourself comfortable, warm and dry. This will not only help prevent a cold, but you’re likely to stay outside longer getting exercise (which is great for your immune system) and enjoying fresh outdoor air where viruses struggle to spread.