The ICSC-Goldman Sachs weekly tracking report indicated sales dropped 0.9 percent from the previous week, although sales rose 2.8 percent from the same week of 2012.
The weekly retail survey released Wednesday said demand was stronger at department, clothing and electronics stores, but "considerably softer at discounters and wholesale clubs."
Weather Trends International said the week was slightly cooler than the same period of 2012, but 0.5 degrees Fahrenheit above the historic average for the week.
The Energy Information Administration said the national average price of gasoline fell to $3.645 per gallon in the week, which is 0.7 percent lower than the same week of 2012.
In theory, falling gasoline prices can allow for more spending elsewhere. The price of gasoline "can affect discretionary income and spending," the trade group said.