This summer, the national real estate market reached five months of supply nationally, putting it in a “rare state of balance,” according to a new Realtor.com report.

Months of supply is a common industry gauge of housing market balance, measuring how long it would take to sell all homes at the current pace if no new listings were added. Realtor.com defines fewer than four months as a seller’s market, four to six months as balanced and six or more as a buyer’s market.

As a result, this is the “most buyer-friendly summer” since Realtor.com began tracking the metric in 2016, Jake Krimmel, senior economist at the site, tells CNBC Make It.

The shift is especially pronounced in large metro areas across the South and West, where faster inventory growth has shifted leverage toward buyers. In Florida, high insurance premiums and other costs have further dampened demand.

Out of the 50 largest metros in the U.S., seven have crossed into buyer’s market territory, with six months or more of supply, based on June data, the most recent available. Additionally, 23 of the largest metros are balanced and 20 still favor sellers, the report says.