NEW YORK CITY—The latest S&P/Case-Shiller Home Price Indices show a continued slowdown in home prices nationwide, S&P Dow Jones Indices said Tuesday. Conversely, the Commerce Department announced that new home sales across the US for December reached the highest monthly tally since before the economic downturn.

Tuesday's Case-Shiller indices, covering home prices for November 2014, show year-over-year growth rate declines for both the 10-City and 20-City Composites. The 10-City Composite gained 4.2% year-over-year, down from 4.4% in October. The 20-City Composite gained 4.3% year-over-year, compared to 4.5% in October. On the other hand, the S&P/Case-Shiller US National Home Price Index, which covers all nine US census divisions, recorded a 4.7% annual gain in November versus 4.6% for the previous month.

“Strong price gains are limited to California, Florida, the Pacific Northwest, Denver and Dallas,” says David Blitzer, managing director and chairman of the index committee at S&P Dow Jones Indices. Elsewhere on the East Coast, as well as in the Midwest, the yearly gains were more modest, with Detroit posting the steepest monthly decline at 0.9%.

“Most of the rest of the country is lagging the national index gains,” Blitzer adds. “Moreover, these price patterns have been in place since last spring. Existing home sales were lower in '14 than 2013, confirming these trends.”

That being said, new home sales rose 11.6% month-over-month in December to reach an annualized pace of 481,000 homes. That's the highest figure since June 2008, and exceeded all estimates from 75 economists polled by Bloomberg. The Commerce Department also revised upward the sales figures for the past three months by 11,000 units, although November sales were revised downward to 431,000 new homes from the previously reported 438,000.

However, Patrick Newport and Stephanie Karol, chief US economists for IHS Global Insight, would likely recommend keeping the champagne corked up for now. “This was a good report, but should not be heralded as a sea-change in sales,” they wrote in a note Tuesday. “None of the sales figures in this report passed a test for statistical significance. However, price growth was solid, and a three-month moving average does reveal a brisker sales pace in most regions of the country,” aside from the Northeast.