Mortgage and refinance interest rates today, December 20, 2025: Why do published rates vary so much?

Mortgage rates are clinging just above 6%. According to Zillow, the average 30-year fixed mortgage rate is 6.03%, and the 15-year fixed rate is 5.42%. Why are Zillow's rates usually lower than those reported by Freddie Mac and elsewhere? Each source compiles rates by different methods. Zillow gets rates from its lender marketplace and Freddie Mac pulls information from loan applications submitted to its underwriting system. Mortgage rates vary by state, by lender, loan type, and many other factors. That's ...