Retailers are bracing themselves for a run on BBQ food as forecasters predict the hottest weekend of the year so far.
Marks and Spencer said it predicted sales of meat to be up 30% on this time last year, and an increase of 25% on last week.
It expects its customers to make their way through more than 700,000 burgers, almost 250,000 "posh dogs" sausages and 500,000 rolls.
It also expects ice lolly sales to be up 150% on this time last year.
An M&S spokeswoman said: "With temperatures set to hit the early 20s, we're predicting this to be the first official BBQ weekend of the year so far.
"We know our customers have been itching to dust off their BBQs and picnic mats, so we are stocking up our shelves with delicious burgers, sausages and picnic treats to ensure we keep up with demand."
M&S is also launching what it claims is the first pre-mixed negroni, the classic cocktail made of Campari, gin and sweet vermouth which is reappearing in bars and restaurants across the UK.
Tesco said many stores had already seen demand soar for BBQ meats, salads, beer, wine, Pimm's, ice cream and bags of charcoal.
The retailer uses an automated ordering system that combines weather data and customer behaviour over the last five years to produce predictions for demand in stores across the UK.
It can calculate accurately how much sales change in a region for every degree of temperature and every hour of sunshine.
The system updates three times a day and can re-calculate within 30 minutes what foods need to be on the shop floor, according to the supermarket.
Tesco BBQ meats buyer Emily Stuart said: "Brits are among the keenest BBQ fans in the world but for much of the spring they have been denied the pleasure because of dull or rainy weather.
"Now with weathermen predicting the warmest weekend of the year, shoppers are wasting no time in stocking up and judging by strong early sales many people will be spending the next few days enjoying al fresco dining in their gardens."
The supermarket said it expected to sell 200,000 steaks, 100,000 barbecue chicken packs, one million packets of sausages, 25,000 packets of halloumi cheese and one million ice lollies over the weekend.
Sainsbury's is predicting customers will get through one million burgers, 10 million sausages and 1.2 million punnets of strawberries, with suncare expected to see a 250% uplift in sales.
A Sainsbury's spokeswoman said: "We know that a weekend of sunshine means that the BBQs will be coming out across the country as friends and families get together to make the most of the weather.
"Customers trust us to deliver quality fresh foods all year round and our weather gurus helped us predict this lovely sunshine so we've kept pace with demand."