The benchmark 30-year fixed rate mortgage rate rose to 6.66% from 6.58% last week, mortgage buyer Freddie Mac said Thursday. One year ago, the average rate was 6.72%.

The 30-year fixed-rate mortgage reached 6.66% on average Thursday.

The average long-term U.S. mortgage rate rose for the fourth consecutive week to its highest level in a year, another setback for prospective homebuyers hoping for a break from…