Fogged windshield questions

It's not a climate exclusive thing, as far as I know. I have had a few cars like that. Always around the edge of the windshield. I always lived with it, but it's less annoying than the pitted windscreens on my current and past daily drivers. Not my fault, I buy used cars, and both P.O.'s must have been typical New England douchebag tailgaters.