A quick way to find out what the interest rates is for mortgage loans is to follow the 10yr treasury yeild.

Notes: The mortgage spread is defined as the 30-year mortgage rate minus 10-year Treasury yield. Its typical range is 1.5 percent to 1.75 percent (150 to 175 basis points).
Source: Freddie Mac, Board of Governors of the Federal Reserve, and author’s calculations; data accessed via FRED