U.S. chain store sales (search) slowed in the fourth week of September, as retailers complained of sluggish sales due to weather, a report said on Tuesday.

Sales in September to date were up 0.4 percent compared with the same period in August, while sales at major retailers rose by 2.9 percent on a year-over-year basis for the week ended September 24, said Redbook Research (search), an independent company.

"Sales slowed in the fourth week as consumers continued to avoid cool weather merchandise due to warm weather in most parts of the country," Redbook said.

"If sales don't pick up, retailers are expected to markdown early in order to clear inventory and make room for holiday goods in October," Redbook added.

The Redbook data are compiled from a sample of same-store sales at general merchandise retailers representing about 9,000 stores. Same-store sales measure revenue at stores open at least one year.