Cool summer weather continued to chill Michigan retail sales in July, the Michigan Retailers Association reported today. It also put a damper on retailers' expectations for the next three months.Forty-five per cent of Michigan retailers reported sales increases in July over the same month a year ago, while 40 per cent reported decreases, according to the Michigan Retail Index - the worst July on record since the Index was established in 1994 by the Michigan Retailers Association (MRA) and Federal Reserve Bank of Chicago.Sales performance has been below normal throughout the spring and summer. Although June showed some rebound, April's and May's figures also were the worst on record for those months.Two-thirds of Michigan retailers expect to increase year-to-year salesduring the August-October period. However, the level of optimism is usually higher at this time of year."Most retailers are happy this summer is coming to a close," said Larry Meyer, CEO of MRA and a former director of the Michigan Department of Commerce. "Cool weather, higher interest rates and higher gas prices have taken a toll.""But continued cool weather can help push up retail sales for the back-to-school and fall seasons," Meyer added. "An early fall could be the retailers' friend."Apparel retailers reported sales gains of 45 per cent.