Supermarket sales in July fell for the 32nd consecutive month, 4.7 percent from a year earlier to 1.424 trillion yen, the Japan Chain Stores Association said Friday.
The year-on-year percentage change is adjusted for a change in the number of stores.
While the summer heat helped sales through the first half of July, overall sales slowed during the second half as temperatures abated, the industry group said.
Food sales, accounting for 51.7 percent of overall supermarket sales, dropped 2 percent to 736.56 billion yen, while clothing sales, which accounted for 17.5 percent of overall sales, slipped 7.2 percent to 249.78 billion yen.
Sales of daily commodities, including sundry items, medical and cosmetic goods, furniture, and electrical appliances, accounting for 21.1 percent of overall sales, fell 6.8 percent to 300.04 billion yen.
Revenue from ticket sales, travel-related business, and other services, which accounted for 1 percent of overall sales, rose 2.2 percent to 13.8 billion yen.
The sales data covered 6,626 outlets run by the association's 109 members.
Meanwhile, a separate report released the same day shows sales at department stores across the country fell 1.5 percent in July from a year earlier to 839.3 billion yen after posting a 2.4 percent rise in June.
The Japan Department Stores Association attributed the fall to shrinking demand from large-lot customers. The reporting month also had one Saturday less than the same month last year, they added.
The group's report covers 295 outlets run by its 121 members.
Combined sales at stores in the country's six major cities fell 1.6 percent in the first decline in four months. The cities are: Tokyo, Osaka, Kyoto, Kobe, Nagoya and Yokohama.
Sales in other cities dropped 1.3 percent, marking the first decline in two months.