The Northeast region outpaced the rest of the United States in pending sales in December, according to the National Association of Realtors. The organization says the pace of pending sales was largely unchanged from November, but again posted an increase from the previous year.

The organization's Pending Home Sales Index for December stood at 106.8. This was only slightly up from November, which had a downwardly revised figure of 106.7. However, it was up 4.2 percent from the December 2014 figure of 102.5. The index has seen a year-over-year increase for 16 months in a row.

The PHSI is a measure of transactions where a contract has been signed by the sale has not closed. Typically, the deal is finalized within one or two months of the signing. The PHSI typically represents about 20 percent of existing home transactions in the United States. A figure of 100 indicates that contract activity is equal to that of 2001, when existing home sales fell into the normal range of 5 million to 5.5 million homes per year.

In the Northeast, the PHSI increased to 97.8 in December. This figure was up 15.3 percent over the previous year and 6.1 percent from November.

"Warmer than average weather and more favorable inventory conditions compared to other parts of the country encouraged more households in the Northeast to make the decision to buy last month," said Lawrence Yun, chief economist at the National Association of Realtors. "Overall, while sustained job creation is spurring more activity compared to a year ago, the ability to find available homes in affordable price ranges is difficult for buyers in many job creating areas. With homebuilding still grossly inadequate, steady price appreciation and tight supply conditions aren't going away any time soon."

Yun says healthy conditions in the American labor market could encourage more people to buy a home, although others may hold off due to losses in the stock market and slowdowns in the energy industry. He says buyers may also be encouraged by continuing low mortgage rates, which continue to hover around 5 percent.

Despite the noticeable increase in pending sales in the Northeast, activity slowed down in other regions. The West had the largest decline from November, with the PHSI for the region falling 2.1 percent to 97.5. However, this index was still 3.4 percent higher than the figure for December 2014.

In the Midwest, the PHSI fell 1.1 percent to 103.6, which was a 3.6 percent increase from the previous year. The PHSI for the South was 119.3, down 0.5 percent from November but 1 percent higher than December 2014.

Yun says existing sales for 2016 are expected to be about 5.34 million homes. This pace would be a 1.5 percent increase from 2015.

The expected increase in sales is considerably slower than 2015, when existing home transactions went up 6.5 percent compared to the previous year. Median prices for existing homes are expected to rise between 4 and 5 percent, down from the 6.8 percent increase in 2015.

The National Association of Realtors predicts that increases in rent will start to slow, declining from an average increase of 3.6 percent in 2015 to a 3.3 percent increase this year. The organization expects that construction on 420,000 multifamily housing units will begin this year, which would be the highest level of activity since 1987.