Temperatures are rising as spring winds down, but there will be no lazy lolling on the beach for would-be home buyers this summer, judging by the state of home buying in the U.S. in May.

Driven by an ever-scarcer supply of available homes, prices for residential real estate reached new heights in May—and homes were scooped swiftly off the market by a lucky few among the hordes of wannabe buyers, according to new data from realtor.com®.

Earlier this spring, the nationwide median home list price pushed above $250,000 for the first time. Now at $275,000, the median list price is 10% higher than one year ago. And prices show no signs of easing.

In fact, inventory levels right now are a bit like one of those good news/bad news jokes. The good news: The inventory of homes for sale increased slightly from April to May, with 560,000 new listings. The bad news: That was still a drop of 11% from May of last year—not nearly enough to keep up with snowballing demand. Much of the new inventory is being quickly swallowed or is priced beyond the reach of the average buyer.

“With a record number of home buyers out there, this is officially the most competitive, fastest-moving spring housing market in decades,” said Javier Vivas, manager of economic research at realtor.com. “Following a furious start to the season, the median days on market for homes on realtor.com in May is the lowest since the end of the recession, and marks the first time that 1 in 3 homes is selling in under 30 days nationally.”

The median age of properties on realtor.com in May is 60 days, which indicates that properties are selling five days (8%) faster than this time last year, and two days faster than last month.

“The lack of affordable inventory remains a critical issue, particularly for a growing number of first-time home buyers and millennials lining up for starter homes and urban dwellings.”

So where in the U.S. are things the craziest—those places where homes fly off the market the fastest, and buyers are up all hours, clicking on listings? When we pulled together this month’s list of the hottest markets in the country, the top markets were a one-two punch for the Bay Area, with San Francisco (including nearby Oakland and Hayward) at No. 2 and Vallejo, just to the north, at No. 1.

Meanwhile, San Jose, a perennial No.1 on this list, slid to the ninth spot, its lowest ranking in months. It’s a volatile housing market out there.

A couple of newcomers cracked the California club that dominates the top rankings. Boston (whose metro area includes Newton and Cambridge) made it to No. 3, its first time in the top five, and Kennewick-Richland, WA, near the Oregon border, rose to No. 5 after ranking at No. 17 the previous month.

The hot list

Rank (May) 20 Hottest Markets Rank (April) Rank Change
1 Vallejo, CA 1 0
2 San Francisco, CA 2 0
3 Boston, MA 6 3
4 Sacramento, CA 3 -1
5 Kennewick, WA 17 12
6 Colorado Springs, CO 8 2
7 Columbus, OH 12 5
8 Midland, TX 32 24
9 San Jose, CA 7 -2
10 Stockton, CA 5 -5
11 Fort Wayne, IN 14 3
12 Dallas, TX 9 -3
13 Grand Rapids, MI 20 7
14 Santa Cruz, CA 11 -3
15 Ann Arbor, MI 16 1
16 San Diego, CA 13 -3
17 Denver, CO 10 -7
18 Detroit, MI 26 8
19 Santa Rosa, CA 4 -15
20 Chico, CA 18 -2