Why does cold weather lead to a cold and fever? Why is cold a factor inducing colds?

Everyone has this experience, so it is easier to catch a cold when it is cold. For example, when the temperature changes in winter or autumn and winter, it is easy to catch a cold when clothes are not added in time to cool down. First of all, because the resistance of our respiratory tract decreases in cold state, we are more vulnerable to virus attacks; The second reason is that these viruses that cause our respiratory tract infections are in a cold environment; Its reproduction is more vigorous. So in this case, our upper respiratory tract infection is mainly viral infection, but we find that more patients catch a cold in cold weather, mainly for these two reasons.