A new Twin Cities real estate index shows the median sale price of Twin Cities homes dropped in August, a time of year when sales are typically more robust.

The overall Twin Cities residential real estate index from the University of St. Thomas, which uses a variety of measures to reflect the health of the market, was essentially flat for August, climbing 1 point to 800 from 799 in July.

The decline in the median sale price -- one component of the index -- was offset by a rise in the number of sales that closed, and better readings for the supply of homes on the market and the number of days on the market.

Three companion indexes fell. The index for traditional home sales, which excludes foreclosures and short sales, fell three points in August to 917 from 920 in July. The short sale index fell, as did the foreclosure index.

It's the second month in a row that the median price on traditional home sales has dropped, according to the index.

"This is concerning, since prices normally reach their highest levels in the spring and summer," said Herb Tousley, director of real estate programs at the University of St. Thomas.

The index, now in its third month, tracks nine data elements to gauge the state of the housing market in the 13-county metro area.

Jennifer Bjorhus • 612-673-4683