WASHINGTON (AP) — Average U.S. rates on fixed mortgages this week fell for a second straight week as the spring home-buying season has gotten off to a slow start.

Mortgage buyer Freddie Mac says the average rate for the 30-year loan declined to 4.21 percent from 4.29 percent last week. The average for the 15-year mortgage eased to 3.32 percent from 3.38 percent.

Mortgage rates have risen almost a full percentage point since hitting record lows about a year ago.

Warmer weather has yet to boost home-buying as it normally does. Rising prices and higher rates have made affordability a problem for would-be buyers, while many homeowners are reluctant to list their properties for sale.

Roughly a third of homeowners owe more on their mortgage than they could recoup from a sale.