30-Year Fixed Mortgage Rate

What this measures — and why it matters in Philadelphia

Freddie Mac has surveyed lenders every week since 1971 for the average rate on a 30-year fixed mortgage, making this the longest-running and most-quoted measure of U.S. home financing costs. It is a national number, but it is the same rate a Philadelphia buyer is quoted, and it moves with the 10-year Treasury yield plus a spread.

No single variable does more to set housing affordability. Each percentage point on this chart moves the monthly payment on a typical mortgage by roughly 10%, which is why rate spikes freeze transaction volume: buyers lose budget and existing owners with cheap mortgages refuse to sell into a higher rate. That lock-in effect throttles inventory in rowhouse neighborhoods just as surely as in the suburbs.

For a Philly investor, the chart is a cost-of-capital dashboard. Falling rates expand the buyer pool and compress cap rates; rising rates do the reverse, usually with a lag of a quarter or two before it shows in deed volume and prices. Reading this series alongside local permits and home prices tells you whether the market's fuel line is opening or closing.

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