That's down from the 4.32% rate last week, and significantly below the 4.87% rate that prevailed at this time last year.
"The 12-month growth rate in the core price index for personal consumption, which the Federal Reserve closely tracks, has been drifting lower over the past six months ending in August and suggests inflation is running at a tepid pace at best," said Frank Nothaft, Freddie Mac's chief economist, in a statement. "This allowed mortgage rates to ease to new or near record lows this week."
The Oct. 7 weekly rate also comes in under Freddie Mac's previous fourth-quarter forecast of a 4.5% fixed rate, she noted.
Freddie Mac expects to release its October outlook as early as Friday or early next week, said Nothaft in an interview.
"We're looking at projections for October right now and there's a good we may reduce our outlook for the fourth quarter, but I wouldn't look at a reduction to 4.0% because I think rates are as low as they can go," Nothaft said. "The quarter may stay around 4.25% to 4.3%, but not as low as 4.0%"
Meanwhile, 15-year fixed-rate mortgages fell to a new record low as well, hitting 3.72% with an average of 0.7 points. Last week, the interest rate averaged 3.75%.
Typically, when mortgage rates drop two things tend to happen: Existing home buyers tend to rush to their banks to refinance their mortgages, while folks who were considering buying a home step into the market or buy more expensive homes than they had previously planned because the decrease in interest means their monthly mortgage payment will be lower.
The National Association of Realtors said applications for home purchases have climbed more than 14% since the end of August through the week ending Oct. 1.