I was born in Missouri. When we would go back in the winter, 40 degrees was colder than zero in Wyoming, where I grew up.
It's the humidity in the south that makes winter seem much colder there than the thermometer reads. I can't imagine negative wind chill in the south. That would be bitter cold and would go right through you! Wind gets us in the north too, but 20 degrees, no wind
and sunny, we can wear shirt sleeves (almost).
There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.