WASHINGTON (MarketWatch) — Sales of new homes surged nearly 19% in May to the highest annual level in six years, though the surprising gain was partly spurred by a big spike in the Northeast that’s unlikely to last.

New U.S. homes sold at an annual rate of 504,000 last month to mark the sharpest increase since May 2008, the government said Tuesday. Economists polled by MarketWatch had expected the pace of sales to rise to a 440,000 rate from a revised 425,000 in April.

The quicker pace of sales in May compared to April reflected the biggest one-month increase in 22 years.

The surge was spearheaded by a 54.5% gain in the Northeast, the biggest advance in almost two years. Yet the region typically has the fewest sales in the U.S. and the seasonally adjusted numbers can be particularly volatile. Just a month before in April, for instance, sales in the Northeast were the lowest in nearly two years.

Still, demand for new housing also showed renewed strength in the West and South, the regions with the highest number of home sales. Sales shot up 34% in the West and 14.2% in the South. In the Midwest sales rose a scant 1.4%.

“The data are highly volatile and the surge in May is clearly exaggerated,” said Jim O’Sullivan, chief economist of High Frequency Economics, but “the housing recovery appears to be getting back on track.”

The uptick in sales occurred despite another rise in prices. The median price of a new home advanced 6.9% year-on-year to $282,000. Read more about prices of existing homes.

Buyers are always more eager to purchase in the spring months, but an unusually harsh winter may have prompted some people who might have bought a house earlier in the year to wait for warmer weather to arrive.

Falling mortgage rates may also be drawing more home shoppers back into the market. A 30-year fixed mortgage dropped to 4.19% at the end of May from 4.43% in January, according to giant lender Freddie Mac. Lower rates may have helped boost sales of previously owned homes in May to fastest rate since last fall.

The supply of new homes on the U.S. market, meanwhile, dropped to 4.5 months at the current sales pace from 5.3 months in April. The number of homes on sales nationwide was unchanged in May, though home builders have applied for more permits to expand the supply of properties for sale. Economists expect sales to pick up as the year wears on, though not at the same blistering pace as in May.

New home sales were 16.9% higher in May compared to one year ago. In April, however, they were 6% lower, showing just how erratic the report on new home sales can be.

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