Contracts for pending sales of previously owned homes unexpectedly fell in January, a survey showed, brought down in part by harsh weather in the Northeast.

The National Association of Realtors said its pending home sales index, based on contracts signed in January, fell 7.6 percent to 90.4 from an upwardly revised 97.8 in December.

Analysts polled by Reuters had forecast pending home sales, which lead existing home sales by one to two months, would rise 1 percent in January.

Compared to January 2009, the index was up 12.3 percent.