How has climate affected regional population distribution in the US?

Climate affects regional population distribution in the U.S. the same as it does everywhere. People seek out climates they find pleasant, and in which they can feed and house themselves with consistent security and safety. As technological advances enable mankind to overcome limitations of climate, people move in greater numbers into what would otherwise be marginal climatic areas. The best example of this is the invention and widespread use of air conditioning leading to much heavier colonization of the Sun Belt.