Finance director Loraine Woodhouse noted that in the same week last year, the supermarket chain ran a half-price event and significant marketing activity – neither of which ran last week.
She added: “The warm weather towards the end of the week meant many customers chose food and drinks suited to entertaining and outside activities.”
This included deli and seafood ranges, as well as individual products suited to barbecues or picnics, such as packs of rolls and bowls of prepared salads.
Waitrose also saw strong sales of drinks, including beer, rose wine, gin, and fizzy soft drinks.
Loraine said: “Our £10 meal deal was particularly popular as shoppers looked for a quick and easy dinner, rather than spending too much time inside, preparing food.”