The Royal Horticultural Society (RHS) said its orchard at Wisley, Surrey, was seeing early ripening of berries and fruits such as apples and pears and that most gardeners should be in line for an excellent crop.
RHS chief horticultural adviser Guy Barter said: "Everything is running a little bit ahead, though the cold nights we've been having will push it back a bit.
"The whole season has been early, it's been a wonderful growing season, with no frosts, good weather and here we are with autumn approaching and fruits ripening.
"If it's a dry summer apples can be small and hard in amateur gardens, but there's been enough rain to swell the fruit and there's been enough sunshine to sweeten the fruit."
The early fruiting season was down to the early spring the UK had this year, but fruit trees did have just enough cold weather in the winter, which they need to ensure they blossom and produce fruit, he said.