What they mean is you can get the sniffles. Mainly as the cold air irritates the respiratory pathways leading to inflammation. This leave an avenue open for flu and cold viruses. Hence why you usually "catch a cold" after getting those sniffles.

old times made out ya can catch a chill it was thought and old movies as well

A logical error, concluding a cause-and-effect relationship because of a (real), evident relationship that is not obviously a direct cause-and-effect relationship. I mean: you have this valid relationship (the number of colds always increases during colder weather), and so someone draws an unwarranted conclusion from that evidence (the unwarranted conclusion: "therefore, cold weather causes colds"). Note that I've heard other unwarranted conclusions. E.g. "Being out in cold weather reduces your body temperature because of lost body heat. Because of this, your body is less resistant to infection and more susceptible to contracting a cold". I don't have any reason to believe that idea is any more true than the "cold weather causes colds" thing. I mean: if it were true, shouldn't we also have a notable increase in - say - plague and leprosy and all other viral and bacterial based diseases during Winter? (But...maybe there IS an increase in all diseases during colder months. If there is, I don't know about it.) *** MY GUESS is that it's not the colder weather itself, or some cold-weather-caused weakening of the immune system, but rather simply the tendency of people to remain together indoors for longer periods of time. I.e. increased human contact and interaction in confined spaces.

Is it just a coincidence that the cold & flu season comes as the weather gets colder? Being exposed to colder temperatures compromises the body's heat retention and disrupts the immune system's optimal efficiency. Consequently, when exposed to a virus, a cold is likely to develop.