Get ready for the next weather phenomenon: fog

Spring was glorious. Summer was the wettest ever. So, in the record year of British weather ups and downs that is 2007, what phenomenon can we expect from autumn, which begins today? The answer is fog.

The Atlantic lows which have dogged the British Isles almost continuously for the past three months, giving us our monsoon summer, are likely to give way now to many more settled periods of high pressure, according to the Met Office's autumn forecast, issued last week. Rainfall and windy weather are likely to be below average, and in the still, calm conditions, fog is more likely to form, especially after the autumn equinox of 21 September when nights become longer than days – and so chillier.

"There will be a greater risk of fog, compared to normal, during the latter part of autumn," said the chief forecaster, Nick Graham. "As the nights get longer and colder it may cause more impact, as it is likely to linger longer during the morning."

It makes more likely Keats' description of autumn as that "season of mists and mellow fruitfulness" – although there is some doubt about the fruit, because of the year's earlier topsy-turvy weather pattern.

For much of the natural world, the wonderful early start to the breeding and growing season provided by the warmest April on record was cancelled by the deluges of the height of summer. So the picture is mixed on how many hips, haws, sloes, blackberries and hazelnuts that countryside walkers may find in the next couple of months.

The early start to spring meant blackberries fruited very early – they were available for Wimbledon in late June – but since then some of the early fruit has rotted.

A lot of blackberries have been noted as "rotting rather than ripening" by Wiltshire Wildlife Trust. "Add to this the fact that the wet and lack of sun will have depressed yields of 'wild foods' as much as agricultural crops, and we might be looking at a hungry autumn for birds and perhaps small mammals like shrews and voles [seed eaters and insectivores]," said a spokesman for the Wildlife Trusts Partnership. "A lot will depend on specific circumstance – for example, grazers like rabbits will have plenty to eat."

But the stress from the weather seems to have induced some tree species, such as hawthorns, to produce more berries.

And in many places naturalists are beginning to think it may be a very good autumn for wild mushrooms. Wildlife Trusts right across Britain are noticing that there seem to be more mushrooms and toadstools about than usual, with some autumn species already well advanced.