Home sales unexpectedly jumped 5.7% in December from the month before, according to a report from real estate franchiser RE/MAX.

Sales usually fall in the winter months. But homes continued moving late last year, up 1.1% from December 2010. It’s the sixth consecutive month of yearly increases. Home prices, however were nearly flat from the previous month and down 3.5% from last year. The median sales price for homes sold in December was $179,587, RE/MAX said.

“We’re pleasantly surprised to see the year end with such strong sales, and hope this trend will continue into the traditional spring selling season,” said Margaret Kelly, CEO of the company.

Kelly added the increase may be due to the larger role investors are playing in the market.

“This December jump may be due to increased investor involvement and transactions that were scheduled to occur before the end of the year, but with prices at or very near the bottom and historically low interest rates, consumers are finding real value in this market,” Kelly said.

Sales made the highest jump in Providence, R.I., where volumes increased 32% from last year. Sales also rose 24% in Wilmington, Del. And 19% in Miami, one of the highest foreclosure rates in the country. Prices increased nearly 17% there as well.

The average days homes spent on the market before being sold in December was 98 days, just one day on average than the previous month and two days higher than one year ago.

Inventories continue to decline. In the 53 metro areas RE/MAX data covers, the amount of homes ready for sale dropped 11% in December from November and remains more than 25% down from last year. Currently, the national market holds a 7.8-month supply, down from a 10.2-month inventory one year ago.

Write to Jon Prior.

Follow him on Twitter @JonAPrior.