The average long-term mortgage rate in the United States rose for the fifth straight week, reaching its highest level in nearly seven months, adding to the affordability challenges faced by homebuyers during the crucial spring housing season, according to the Associated Press.Mortgage buyer Freddie Mac said the benchmark interest rate on a 30-year mortgage rose to 6.46% from 6.38% last week. A year ago, the average rate was 6.64%.The last time the average rate rose was on September 4, when it was recorded at 6.5%.Higher mortgage rates can significantly increase buyers’ monthly payments, often adding hundreds of dollars in costs and reducing purchasing power in an already stressed housing market.Just five weeks ago, the average rate fell to just under 6% for the first time since late 2022, but it has since reversed course. This rise comes at a time when rising oil prices linked to the Iranian war have increased concerns about inflation.Meanwhile, borrowing costs on 15-year fixed-rate mortgages, which are typically used for refinancing, also rose. Freddie Mac said the average rate rose to 5.77% from 5.75% last week, compared with 5.82% a year ago.