New Census Bureau estimates reveal that Florida has overtaken New York in size.  In the New York Times article "New York Soon to Trail Florida in Population," Jesse McKinley recently examined how the Sunshine State has become the third most populous state.  He cites data and analysis from Social Explorer's Andrew Beveridge:

The census figures underscore immigration trends, as foreign-born migrants continue to move to warm-weather states such as California and Texas — No. 1 and 2 — as well as to Florida. The newcomers also include winter-weary New Yorkers who move or retire to Florida at a rate of over 50,000 a year, twice the number of Floridians who head to New York.

But the shift also highlights the struggles in upstate New York, which has lost large-scale manufacturing jobs and large chunks of population, offsetting consistent gains in New York City. But the city’s growth has seemingly not been robust enough to stave off hubs in Florida like Jacksonville, Miami-Dade County and Tampa.

“It’s going to happen,” said Andrew A. Beveridge, a professor of sociology at Queens College and an expert on the census, on New York’s falling into fourth place. “And if Florida accidentally grew faster and New York slowed down, it could have happened already.”

Beyond a blow to New Yorkers’ collective ego, the changing population pattern could have many practical and political implications, including diminished congressional delegations, a setback New York already suffered in 2010 — the year of the last decennial census count — when the state lost two districts, while Florida gained two seats. Census data also inform how billions of dollars in federal funding and grants are divvied up among the states, for things like highway planning and construction, public aid for housing and health care and education programs.

Beveridge talks more about the population shifts and causes on WNYC's The Takeaway in "American on the Move."  Listen to the segment on everything from air-conditioning to migration to the housing market:

That’s really been going on ever since the advent of AC right after WWII.  The growth pattern for domestic migrants and also for international migrants has been  more and more to the southwest and the south, to places like Florida.  And this has been going on really for quite a while…

It translates into lots of different things including Texas picking up four congressional seats and New York losing two congressional seats after the last census came out.

He goes on to discuss the population shifts within New York State, and the major factors behind the population trends–births, death, international migration, domestic migration, and the job market.