In 2010 UK supermarket chain Sainsbury's cashed in on a sunny start to spring with a heads-up from MetraWeather.
The retail giant's profit margins depend on juggling 30,000 product lines across 934 stores. In winter, long-life items such as woolly scarves, cat litter, tinned soups and red wine gain valuable shelf space, along with perishables such as warming puddings and root veges for stews and roasts. In summer, these make way for white wine, beer, salad greens and ice cream.
A decade ago, ten percent of perishable products were written off as waste. Now, with more sophisticated customer demand prediction, it's just one percent.
"We spotted the signal for the first warm weekend nine days out and nailed it," says MetraWeather's Tony Ramsay. "So long as it's sunny, people will crawl out of their winter hibernation, and barbecue and picnic-related sales will soar."
MetraWeather works with six major supermarket chains in the UK plus 20 smaller companies across retail, the energy sector and the media. Services range from nationwide weather projections six months ahead, to local five-day forecasts that pinpoint areas by post code and are updated four times a day.
MetraWeather's team of ten meteorologists often phone customers to explain the data, clarify weather fluctuations and offer advice.
"Temperature is the key driver, but it's not the only one," Tony says. "Ice cream sales go through the roof over a long warm period. Mum buys multipacks, but when there's a sudden increase in temperature, last minute buys of single ice creams kick in."
April 2010 was the UK's warmest on record and retail sales jumped 1.1 percent - the biggest hike in nine years. With the UK grocery market worth over £150 billion annually, it certainly pays to know what's in store weather-wise.