Usually at this time of year the orchards that ring the foot of Glastonbury Tor are heavy with fruit. "But look at them now – they're miserable," says Jim, a landscape gardener from Bristol, who makes an annual pilgrimage to the hill in Somerset to walk and to scrump a few apples. "I know it's a bit naughty but it's become a kind of tradition for me. I clamber up the hill and then help myself to a few apples. This year there's hardly any to be seen."

Throughout the UK, apple growers, cider-makers and gardeners are complaining about the worst apple yield for 15 years. The cold, rainy summer, which discouraged the bees from flying at crucial periods, has left many orchards bare and gloomy.

Adrian Barlow, the chief executive of the growers' organisation, English Apples and Pears, said the crop was likely to be the worst since 1997 when a late frost damaged orchards. "It is going to be a tough time not only in the UK but across Europe," he said.

Harvesting is around three weeks behind in many places and apples already picked, such as the Discovery, have proved to be of poor quality. Retailers are reducing their specifications and accepting apples with more skin markings than normal but prices are still likely to rise.

A tour of the National Trust's orchards at Barrington Court, 20 miles south-west of Glastonbury, reveals the extent of the problem. In the Goose Orchard where cider apple varieties such as the Yarlington Mill, Slack-Ma-Girdle and Hens' Turds usually thrive, many trees are bare or carrying just a few miserable fruit.

"It's a bit sad and it worries me slightly," said Rachel Brewer, the trust's sommelier (its maker of Somerset cider and apple juice). Usually, if the apple trees at any of the five trust properties used to create the cider and juice – including the orchards at Glastonbury Tor – fails, the others make up for it. This time all have struggled.

"The blossom just didn't come on many of the trees and the bees didn't fly because of the rain and wind. You get used to trees having some bad years so hopefully they are just having a rest and will be fine again next year," she said.

Brewer will have to use every last apple to make sure she can produce enough of its cider and juice to satisfy demand.

"For the last two or three years we've had bumper crops," she said. "This year it's been really disappointing. We usually try to leave some of the apples for the wildlife, the insects, the birds, the badgers but this year we're going to have to use it all."

Elsewhere, the National Trust is reporting the same pattern. In Dorset, cider apple trees are bearing only a tenth of the fruit they produced last year.

In Surrey, a cider-making day has been cancelled. There are no apples on mature trees at Hardcastle Crags in the South Pennines and no crab apples in the woods.

Common Ground, the environmental and art charity that promotes apple days and traditional varieties of apples, said orchard owners had been "throwing their hands up in horror" at the crop.

Large producers of cider are also having to cope with a more variable crop than they have become used to in recent years. Rod Clifford, production director at Aston Manor Brewery, which has 300 acres of orchards in Herefordshire and Worcestershire, said: "Certainly there is more variation in recent years with orchards in near proximity producing very different crops. What I have noticed is that young trees are doing better than might have been thought – I suspect this is because the quality of orchard husbandry is increasing, particularly by those producers and growers that have made the investment decision to plant new orchards."

The story is similar for Bulmers, the UK's largest producer of cider. Gabe Cook, cider communications manager, said there was a "lack of uniformity" across farms and locations.

Paul Bartlett, the chair of the National Association of Cider Makers, said the industry was resilient, but added: "The increasing incidence of extreme weather have really buffeted our industry."

Back at the foot of Glastonbury Tor, Jim gives up in his quest for apples and heads off to the town centre in search of his fruit fix, hoping for a better summer and apple crop next year.