Despite a cooling real estate market, affordable housing in the Washington region will become even more elusive this year as interest rates rise and home prices continue to outpace the national average, according to an annual report released today by the Joint Center for Housing Studies of Harvard University.

The median price of a home in the Washington region hit an all-time high last year at $424,700 — 5.8 times the region’s median household income — and although housing appreciation is expected to slow down, it won’t be enough to offset rising interest rates. A 30-year fixed-rate mortgage is expected to average about 6.9 percent during the first half of 2006, according to the National Association of Realtors.