Mortgage rates fell this week, with the average 30-year fixed mortgage rate dropping to 6.2 percent. According to Bankrate.com's weekly national survey, the average 30-year fixed mortgage has an average of 0.4 discount and origination points.

The average 15-year fixed rate mortgage popular for refinancing retreated to 5.95 percent, while the average jumbo 30-year fixed rate was down slightly to 7.61 percent. Adjustable mortgage rates were sharply lower, with the average 1-year ARM down to 5.89 percent and the average 5/1 ARM pulling back to 6.21 percent.

Mortgage rates continue to be volatile, yo-yoing up and down from one day to the next. Heightened economic worries pushed mortgage rates lower versus last week, but the continued twists and turns of the credit crunch are certain to produce more volatility in mortgage rates. Although mortgage rates are pegged to long-term Treasury yields, the spread above risk-free Treasury yields is ever-changing as credit worries prevail. The movement of fixed mortgage rates is not directly influenced by the Federal Reserve's cut to short-term interest rates.

This year has been a wild ride for mortgage rates, with a low in January of 5.57 percent and a high of 6.77 percent in July. At today's rate of 6.20 percent, a $200,000 loan carries a monthly payment of $1,224.94.