When Florida Gov. Ron DeSantis announced he would debate California Gov. Gavin Newsom, he framed the event partially as a competition between the states themselves.

The first point he raised wasn’t about job growth, crime or life expectancy — it was the number of people leaving California.

“The debate between California and Florida has already been had,” DeSantis told Fox News host Sean Hannity in August. “(People have) been voting on it with their feet.”

So what does the data show about migration between the two states?

It’s true that more Californians are moving to other U.S. states than are moving in, and that a greater number of people are moving into Florida than are leaving. In 2022, California lost 340,000 more people to other states and Puerto Rico than it gained. Florida, by contrast, gained about 250,000 — a large share of which was a result of migration from New York.

Historically, California has tended to lose more residents to domestic migration than it’s gained, but has continued to grow because it attracts so many international migrants. But in recent years overall population growth has stalled as domestic out migration rocketed up.

The flow between California and Florida also favors the latter state. About 50,700 Californians became Florida residents from 2021 to 2022, according to data from the Census Bureau’s American Community Survey. That’s 22,100 more than the 28,600 Florida residents who moved to California.

The flow of residents moving from California to Florida has been rising quickly since the beginning of the pandemic. The annual net migration from California to Florida more than tripled from 2019 to 2022.

Still, the net number of people leaving California for Florida is a small fraction of California’s overall out-migration. Larger groups of movers went to closer states like Arizona and Nevada between 2021 and 2022, though Texas had the biggest net in-migration at more than 60,000 former Californians.

Relative to its population, Florida had a fairly small rate of arrivals from California, Census Bureau data shows, just 1 person per 1,000 residents. Idaho, which saw about 21,000 more people come from California than make the opposite move, had by far the highest rate at 11 movers per 1,000 people. Nevada and Arizona had rates of 8.4 and 6.4, respectively. Even Florida’s neighbor Georgia, attracted more Californians as a share of that state’s population.

There’s also some notable demographic differences between the people moving from California to Florida and those who stay in the state. Nearly 60% of Florida residents who moved from California identified as non-Hispanic white, according to data from the Census Bureau’s 2016-2021 American Community Survey, the most recent available. Among people who stayed in California, just 36% identified as white.

Additionally, only about 22% of Californians who moved to Florida were Hispanic, compared to 40% of residents who didn’t change states.

Households moving from California to Florida are also wealthier, on average, than those making the opposite trip. The average household income among people who moved from California to Florida between 2020 and 2021 was nearly $200,000, according to tax return data from the IRS.

The households that moved from Florida to California those years made an average of less than half that amount, just $90,000. And the average income among California households that remained in the state was only about $103,000.

Some research has indicated that, though households of all incomes have left California at higher rates that they’ve moved in, higher earners tend to gravitate toward states with no income taxes, like Florida.

Other studies show California’s high cost of living — and especially its high housing prices — is a major driving force behind the number of people leaving the state. A 2023 poll from the Public Policy Institute of California found that about a third of residents are considering moving to another state, with 45% citing housing costs as a factor.

Reach Christian Leonard: Christian.Leonard@sfchronicle.com