Shares in J Sainsbury PLC (LSE:SBRY) and Tesco PLC (LSE:TSCO) nudged lower in morning trading after figures showed the heatwave continued to weigh on shopper numbers in July.
Total UK footfall fell 2.1% on a year earlier, according to data from the British Retail Consortium (BRC) and Sensormatic, which tracks visitor numbers to retail locations.
That was an improvement on the 3.4% drop recorded in June.
High streets took the heaviest hit, with footfall down 3.8% year on year, against a 6.2% fall the previous month.
Shopping centre footfall was down 1.4%, compared with a 2.5% drop in June.
England recorded the weakest performance of any UK nation, with an overall decline of 3%.
London fared worst, down 5.3%, underlining the difficulties facing large urban centres during periods of extreme heat.
Helen Dickinson, chief executive of the BRC, said the capital was hit particularly hard as soaring temperatures made tube and train travel less attractive.
She said some commuters and shoppers had opted to stay at home.
Dickinson added that climate change continues to deliver more and more extreme temperatures in the UK.
Retailers are responding by investing in mitigations such as additional air conditioning and more efficient refrigeration units, alongside initiatives aimed at cutting carbon emissions, she said.
She argued that business rates often punish stores for such investments, calling on the government to look again at what she described as a broken system.
Andy Sumpter of Sensormatic said six of the first seven months of this year had performed worse than the same period in 2025.
He said the exceptionally hot and historically dry weather was likely to have been a significant factor, discouraging shopping trips and particularly affecting high streets.
Sumpter added that retail had yet to experience any meaningful bounce following the arrival of a new prime minister.
The focus for retailers remains on converting more selective visits into meaningful spend as the summer progresses, he said.
Sainsbury, off 1.7% this week, fell 1%, as did Tesco, which has fallen 3.6% over the last five trading days.
