High mortgage rates -- 7.4% at the moment -- are only a problem if you're, well, using a mortgage. In some of the nation's largest metropolitan areas, many buyers are using a different kind of financing: cold, hard cash.

Why? "Markets with a high share of cash buyers may be somewhat less affected by rising mortgage rates because a smaller share of buyers relies on financing," says Rob Barber, CEO of the property analytics company Attom.

In seven of the nation's 50 largest metropolitan areas, cash buyers already outnumbered those who buy with a mortgage, according to data provided by Attom.

To find the cash-heavy markets, Barron's eliminated any metropolitan area from Attom's data that didn't have cash purchase information available, then slimmed the list down to the 50 largest metropolitan areas by housing units.

The data reflect transactions in the first quarter of the year, the most recent period available, when mortgage rates were largely fluctuating around a lower but still hefty 6.1%.

Three of the seven metropolitan areas where more than half of buyers skipped a mortgage are in Florida. A respective 56% and 59% of buyers in North Port and Cape Coral paid in cash -- the most of all 50 cities.

Among the house hunters who commonly shop with cash are "second-home buyers and homeowners who have enough equity to purchase without financing," says Barber.

Home for-sale listings in both North Port and Cape Coral listed on Realtor.com attract a sizable share of views from out-of-state areas such as New York, Chicago, and Washington, D.C., according to Realtor.com data. That suggests movers from pricier metros are bringing cashed-out equity to the beach along with their flip flops. (News Corp, which owns Barron's, also operates Realtor.com through its Move subsidiary.)

Miami itself is a magnet for cash shoppers. "There's a lot of people who are looking into relocating to Miami that have created significant wealth over the last several years," says Peggy Olin, president and CEO of the Florida brokerage OneWorld Properties.

Just over one in two Miami shoppers pays entirely in cash. Some, says Olin, borrow against their stock portfolio instead of taking out a mortgage, while others, required to pay a hefty deposit for a preconstruction home, simply pony up for the whole purchase.

Other markets are magnets for investors. In the first quarter of the year, more than one in 10 buyers in both Atlanta and Birmingham, Ala., were institutional investors, the Attom data show. Cash purchases in these metros represented 55% and 51% of all transactions, respectively.

The remaining two metros, Albany, N.Y., and Cleveland, stand out for their relative affordability, which makes a cash purchase more possible. In Cleveland, the median home was listed for $259,900 in September, according to Realtor.com -- 38% cheaper than the national average. Homes in Albany, at $419,975, are pricier -- but look cheap by comparison to the $742,000 price tag on homes in the greater New York City metro nearby.

To be sure, other factors, such as local economics and housing policy changes, can quell buyer demand and drive price cuts -- cash buyers or not. "Rising rates can still reduce the overall buyer pool and affect demand," says Attom's Barber.

But expect cash to ramp up in popularity elsewhere -- particularly at the higher end.

"We're seeing a much higher share of all-cash deals at the luxury end of the market, at about a third of sales," says Lisa Sturtevant, the chief economist at home listing data company Bright MLS. The firm operates across a wide East Coast range from New Jersey to central Virginia. "These cash buyers are less interest-rate sensitive than buyers who need to finance a home purchase."

Should cash pick up, it will be the latest sign of an increasingly divided housing market split between home buyers with cash and equity and those without.

"The national housing market may be stagnant, but there is still activity among the highest income buyers and sellers," a team of TD Cowen researchers wrote in a note earlier this month. "It's K-shaped housing in a K-shaped economy."