Whatcom County real estate sales are off to a strong start in 2013, according to a new report.

Local real estate agents sold 142 houses and condominiums last month, making it the busiest January since 2008, according to data from the Northwest Multiple Listing Service. It's a 20.3 percent increase compared to January 2012.

The median price also rose, according to the data. Last month the median price for those homes and condos sold was $235,000, up 6.6 percent compared to a year earlier.

January is typically the slowest time of the year for local home sales, and the strong start continues what was a strong end to 2012, said Darin Stenvers, branch manager at the Bellingham John L. Scott office.

"Buyers are aware of the fact that inventory is low and that interest rates could be moving up later this year," said Stenvers, noting that the lack of inventory is leading to multiple offers.

According to a report by Coldwell Banker Bain, the housing supply locally was estimated at six months at the end of 2012. Six months' inventory typically means a balanced market between buyers and sellers.

Stenvers expects significantly more homes to go on the market in the coming weeks. Spring is usually the time of year when new listings spike, and the relatively mild winter to this point will bring out the new listings sooner than usual, he said.

New listings are already ahead of last year, according to the NWMLS data. Last month had 288 new listings locally, up 19.5 percent compared to 2012.

Much of Washington state experienced stronger sales in January. In 21 counties the NWMLS serves, real estate agents sold 4,289 homes and condos last month, up 23.6 percent compared to January 2012. The median price for those sales was $239,300, up 11.3 percent compared to a year earlier.

In Skagit County 81 homes and condos sold last month, up 22.7 percent compared to January 2012.

Reach Business Editor Dave Gallagher at 360-715-2269 or dave.gallagher@bellinghamherald.com. Read his business blog at blogs.bellinghamherald.com/business or follow him on Twitter at @bhamheraldbiz.