Judging by the numbers, the housing market remains in fragile health. According to data released Tuesday by the National Association of Realtors (NAR), existing-home sales fell 0.6% in February, which is the third monthly decline in a row. Home values also continue to wobble; the Federal Housing Finance Agency (FHFA) said Tuesday that home prices declined 0.6% (yes, the same percentage as existing-home sales) in January, compared to the previous month.

“February's drop in sales is further payback for the first-time home buyers' tax credit that expired on November 30,” asserted Patrick Newport, U.S. economist at IHS Global Insight, a research firm in Lexington, Mass., who added: “The key question remains whether the second home-buyers tax credit will boost sales. So far, the housing recovery is very slow, and the second tax credit appears to be having a minimal effect.”

This second tax credit requires buyers to have a signed contract by April 30 and settlement by June 30.

February’s bad winter weather may have been a factor in those existing sales numbers, resulting in numbers that “may mask underlying demand,” according to the NAR. “Some closings were simply postponed by winter storms, but buyers couldn’t get out to look at homes in some areas and that should negatively impact near-term contract activity,” said Lawrence Yun, NAR’s chief economist.”

At a seasonally adjusted level of 5.02 million units, February’s existing sales numbers are 7% above the same month one year ago, but the 2010 housing market still harbors many unknown factors.

Those include home prices, which continue to be affected by foreclosures, short sales, and similar transactions. According to NAR data, distressed sales contributed 35% of February’s existing-home sales.

Such pressures invariably affect home values, and the median price for an existing home slipped 1.8% on an annual basis to $165,100 last month, based on NAR figures.

Weakness is also showing up in the Federal Housing Finance Agency’s home price index, which dipped 0.6% on a monthly basis in January and 3.3% year-over-year. This government indicator is based upon repeat home sale transactions from all 50 states and the District of Columbia involving conforming, conventional mortgages purchased or securitized by Fannie Mae or Freddie Mac.

In the South Atlantic,  prices were down 7.5% on an annual basis in January. (This includes the states of Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, Georgia, and Florida.)The East North Central region, which incorporates the states of Michigan, Wisconsin, Illinois, Indiana, and Ohio, recorded a 6.9% annual decline. The largest gain came from the Pacific, where prices increased just 1.6% year-over-year in the states of Hawaii, Alaska, California, Washington, and Oregon.

Alison Rice is senior editor, online, at BUILDER magazine.