The British Retail Consortium research shows:
- The most notable impact from the Olympics was felt online, which saw growth of 4.8% in August, the lowest since the BRC started collecting data on internet sales in October 2008.
- Warmer weather in the middle of August helped boost sales of food, especially party snacks such as crisps, nuts and barbecue foods.
- Clothing had an "unusual and rather disappointing" month, the BRC said, as womenswear retailers failed to attract customers to autumn/winter ranges.
More top news
Showers across parts of Wales and southern England on Saturday will be heavy at times.
Thousands of Buddhist and Taoist temples and shrines, along with mosques and churches, were damaged or destroyed under communism.
More than 11,000 fans voted on Twitter.