Conforming mortgage rates are at their highest level this year after increasing 51 basis points since Election Day, according to Freddie Mac.

The 30-year fixed-rate mortgage averaged 4.08% for the week ending Dec. 1, up from last week when it averaged 4.03%. A year ago at this time, the 30-year fixed-rate mortgage averaged 3.93%.

The 15-year fixed-rate mortgage averaged 3.34%, up from last week when it averaged 3.25%. A year ago at this time, the 15-year averaged 3.16%.

"With mortgage rates at the highest we've seen this year, borrowers are now backpedaling on refinance opportunities. The latest Weekly Applications Survey results from the Mortgage Bankers Association show refinance activity down 16% week over week," said Sean Becketti, chief economist at Freddie Mac.

The five-year Treasury-indexed hybrid adjustable-rate mortgage averaged 3.15%, up from last week when it averaged 3.12%, while a year ago it averaged 2.99%.