Total sales at UK supermarkets rose by 4.6% in the four weeks ending June 13, 2026, according to the latest data from NielsenIQ (NIQ). While this marks a slight improvement from the 4.2% growth recorded in the previous month, the headline figures mask a highly volatile few weeks for British grocery retailers.
A sharp heatwave at the end of May initially triggered an impressive 6.3% spike in grocery spending, as consumers rushed to buy summer essentials, ice cream, and outdoor goods. However, the subsequent two weeks saw cooler, wetter weather return to the UK, causing sales growth to plummet to just 0.4% and forcing shoppers to spend £490 million less than the prior fortnight.
Despite the erratic weather, the start of the World Cup has provided a significant cushion for the sector. Promotional spending rose to 25% of all grocery purchases, heavily driven by football-themed discounts. Rapid online delivery services hit a record 12.8% share of online sales, while pre-tournament social gatherings led to an 11.9% surge in soft drinks and a 7.9% increase in lager sales.
