Why can cold weather be dangerous?

Yes, because it can make you sick or give you a cold and lead to other dangerous diseases.

I disagree. Cold in itself doesn't make you sick. It MAY stress your system because it is focused on maintaining homeostasis, allowing you to become more suseptable to viruses and bacteria. But my theory is that cold forces us to spend more time inside closed quarters with other people who are carrying viruses and bacteria. If you have a wet head in the winter, the safest place to be is out in the cold fresh air and not couped up in closed quarters with a bunch of sick people.