||Is it true that catching a cold has nothing to do with being out in the cold?
Yes. A cold is a viral disease. It is passed from one person to the next, usually by way of airborne droplets from a sneeze. You can also pick it up if your hands are dirty (with the virus) and you touch your eyes or nose. Catching a cold has nothing to do with the temperature outside, or whether or not your hair is wet.
Colds are common during winter because people are living and working in close quarters. It's chilly out there, so people tend to stay indoors. Proximity also makes schools, offices, and airplanes "great" places to catch a cold.
Complicating matters, if you catch a cold, you're contagious before you even know it. People are usually contagious about a day before the illness breaks, and a few days after they feel better. Plus, there are over 200 viruses that can cause a cold, and they're constantly mutating.
So what's the best way to avoid one? Steer clear of crowded places, wash your hands, keep your fingers out of your face (a good idea at all times, actually), and make sure your ventilation system is up to snuff. But the main thing is to keep those hands scrubbed.