Wendell Cox notes in a posting at New Geography, that the 2013 annual metropolitan area population estimates by the US Census Bureau show that between 2010 and 2013, 51% of the population increase in the 52 major metropolitan areas (over 1 million population) of the United States was in the South. The West accounted for 30% of the increase.  All but one of the  top ten metropolitan areas for domestic migration were in sunnier climates.  The exception was #9 -- Seattle.