The warmer weather saw divisional sales increase by 4.1% last week to May 14 at Waitrose compared with the same week last year.
The supermarket chain’s marketing director Rupert Thomas said: “Customers were eager to fire up the barbecue and take advantage of the sunshine.”
Barbecue fuel sales rose by 95% and barbecue meat sales were up 17%, while service counter fish sales leapt by 16%.
There was a huge rise in beer and Pimms sales too, up 20% and 72% respectively on the previous year.
Picnic foods also saw significant uplifts with salad sales increasing by 12% and soft fruit by 11%.
Elsewhere, online sales were up by more than 10%.