New Jersey's average APR for a 30-year fixed mortgage is 6.249%, slightly below the national average of 6.258%. The 15-year fixed mortgage rate is 5.413%, and jumbo 30-year fixed is 6.736%. Refinance rates are similarly close to national averages. Rates have generally trended downward over the past three months. To secure the best rates, maintain strong credit, shop lenders, and consider a 20% down payment.