King County’s median sales price for single-family homes and condominiums rose almost 10 percent in December from a year ago, hitting $676,000, according to Northwest Multiple Listing Service (NWMLS) data released Wednesday.

Snohomish County’s median rose 8 percent to $535,000.

While brokers in the 25-county NWMLS system added 5,260 new listings last month, a whopping 39.3 percent more than in December 2019, inventory of homes for sale remained too low for the demand from buyers.

“The velocity of the December market is a harbinger of the 2021 market as tight listing inventory, low interest rates, and high buyer demand continue to drive momentum,” John Deely, executive vice president-operations at Coldwell Banker Bain, said in a NWMLS news release. “Every market serviced by NWMLS was trending below December 2019 for total active inventory. In King County, despite a nearly 62 percent increase in new listings compared to a year ago, the insatiable buyer demand quickly absorbed available properties.”

James Young, director of the Washington Center for Real Estate Research at the University of Washington, noted that as more people work from home, they’re buying properties farther from Seattle.

He singled out Chelan, Clallam, Grays Harbor, Kittitas, and Mason Counties showing year-over-year growth in prices of 20 percent or more.

The NWMLS report also showed Pacific and Whatcom counties with price gains of at least 20 percent.

J. Lennox Scott, chairman and CEO of John L. Scott Real Estate, said in the release, “Housing market activity is truly off the charts.” He described activity for new listings going under contract as “frenzy level,” driven by interest rates and more buyers than homes available.

“Now that the holiday season is over, local housing markets will see a surge of buyers entering the market in 2021,” Scott predicted.

He added that he also sees people who can work from home moving to lifestyle and destination markets farther away from city centers.

The frenzy means buyers have to be ready to step up.

Mike Grady, president and CEO at Coldwell Banker Bain, advised buyers to be patient and prepare for multiple-offer situations.

He cited an example of a recent sale a Coldwell Banker broker facilitated for her buyers on New Year’s Eve.

“The buyers had been looking for months and won a bidding war on a listing located near Monroe by paying 18 percent over list price,” Grady said in the release. “This is the reality of the market and it’s increasingly occurring outside the major metro areas.”