Washing hair before going out ?

Do you guys belive in its bad to shower/wash your hair before going out in the fall and winter . Maybe it's just beliefs but my mom and some of my family including my mother in law believe that it's bad like you can catch a bad cold or even pneumonia. I remember taking a shower early and washing my hair in the morning before going to an appointment and it was in December it was very cold and my mil told me not to that I should of either waited till it dried or done after coming home . Anyway do you guys believe this or is it just a myth/belief?