In Snohomish County, a typical house now costs more than $300,000. On Mercer Island, it's more than $800,000.

Those figures were among the highlights — lowlights if you're looking for a home — from the latest batch of monthly figures released yesterday by the Northwest Multiple Listing Service.

Yes, another month of low mortgage rates and little inventory, another month of a relentlessly hot Seattle-area real-estate market.

The median sales price for all homes (single-family houses and condos) sold during August in King County was $349,950, a jump of 17 percent compared with the same period in 2004.

In Snohomish County, the median price of homes soared 23 percent to $296,725, while the figure for single-family houses soared 24 percent to $311,525, the first time it has climbed above $300,000.

That didn't surprise longtime Snohomish County real-estate broker Vern Holden.

"We're getting closer and closer to Bellevue, aren't we?" said Holden, broker of the Bothell/Mill Creek Windermere Real Estate office.

That brought a laugh from one of his counterparts on the Eastside, Ken Bacon of the Redmond Windermere office, who noted that entry-level single-family homes on the Eastside now cost nearly $400,000.

Holden said the combination of steady job growth fueled by a resurgent Boeing, Snohomish County's location as a "convergence zone" of the Eastside and North King County, and relatively affordable real-estate prices have lured many people looking for homes.

"My son lives in Ballard in a 1,800-[square]-foot home that's worth $400,000," Holden said. "They are getting $250,000 [in Seattle] for one-bedroom condos. That drives everybody out to areas where there is more affordability."

Homes are selling briskly, too. In King County, the typical "for sale" sign was up for 36 days, compared with 46 days the year before. The story was similar in Snohomish County, where the average time on the market dropped from 49 to 41 days.

Despite a steady rise over the past year in short-term interest rates, mortgage rates are tied to long-term interest rates and haven't budged much. In fact, the average 30-year fixed rate mortgage last week was 5.71 percent, down from 5.83 percent a year ago, according to a nationwide survey by mortgage company Freddie Mac.

Another factor at work is the relative lack of homes for sale in the Seattle area. The number of homes listed for sale last month in King County was down 26 percent from a year ago. In Snohomish County, it was down 19 percent.

Many homeowners who might have put their homes up for sale in the past are staying put and often remodeling rather than taking on a larger mortgage.

"They say, 'What can I afford to buy?' " Holden said.

Bill Kossen: 206-464-2331 or bkossen@seattletimes.com