SUNNY DAYS do more than improve moods and spread vitamin D; they also deliver important nutrients to company balance sheets. However the dangers of depending too heavily on the weather for a performance boost were all too clear during the dismal summer of 2007, and several companies will now be scouring the long-range weather forecasts with sales-starved eyes, hoping for brighter days.

"A time to cool down" screamed the billboards advertising the icy appeal of Magners and Bulmers cider last July - when most potential drinkers were thinking it was a time to warm up and dry off. Having launched Magners in Britain in the gloriously hot summer of 2006 and having marketed it as a drink to be poured over ice, CC's cider brand became inextricably linked in British consumers' minds as a refreshment to be sought out during a heatwave. When temperatures struggled last summer, so did sales.

"We're all praying for a scorcher of a summer, but none more so than the board of CC," says a spokeswoman for bookies Paddy Power, which is taking bets on the drinks group's profits.

Another Iseq-listed stock that will be hoping to avoid a rain-soaked summer is Grafton, the owner of the Woodie's and Atlantic Homecare chains. While wet weather sends people hurtling toward their local cinema - or travel agent - blue skies prompt them to whip out paintbrushes and gardening trowels.

So the grey summer months of 2007 meant business at Grafton's DIY stores was something of a damp squib, with the services of the part-time staff hired to cope with seasonal demand proving unnecessary in some cases. March and April 2007 were unseasonably warm, though, making Grafton's sales comparisons for the first four months of this year a little gloomy.

Companies are taking steps to avoid being in such thrall to something as unpredictable as the weather. CC is piloting Magners in Barcelona and Munich, which would make it less reliant on the British and Irish summer.

Meanwhile, ice-cream manufacturers have diversified away from their standard ice-lolly offerings and are also selling less seasonal, occasion-led luxury tubs. It's a move driven by trends in consumer tastes more than anything else, but it also means their profits are less likely to freeze when temperatures dip.