Updated

Average U.S. rates on fixed mortgages rose this week with the spring home-buying season beginning.

Mortgage buyer Freddie Mac says the average rate for the 30-year loan rose to 4.33 percent from 4.27 percent last week. The average for the 15-year mortgage increased to 3.39 percent from 3.33 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.

Sales of new homes fell 14.5 percent in March to a seasonally adjusted annual rate of 384,000, the Commerce Department said Wednesday. Purchases of existing homes also declined last month, the National Association of Realtors said Tuesday.