As I waited for the kettle to boil, I looked out into the back garden and the overall impression was of autumnal dampness. Wet leaves now littered the paved areas, the long sword-like leaves of the pond iris, like me, were looking tired and old, while seemingly everywhere optimistically-spun spiders' webs bowed under their burden of moisture.
Among this sense of the year growing old, there are, however, a few gems which transform the landscape of our gardens and countryside. As the heat of the summer (we did have a little bit) slowly gives way to the on-coming winter, with its cold frosty nights, the colours of the countryside shift from the predominant greens of summer foliage and unripe fruits to the yellows, reds and browns of dying leaves, juicy berries and ripe nuts.

Leaves are the powerhouses of trees and shrubs, producing simple sugars from water and carbon dioxide, through the process of photosynthesis. As autumn draws in, days shorten, the metabolism of most plants slows down, and many mark the end of their growing season, by shedding their leaves.

This is done by the formation of a watertight boundary between the branch and leaf stem. This, the abscission layer, effectively isolates the leaf from the tree, cutting off supplies of food and water. It is here that the joint becomes brittle, allowing leaves to fall away from the parent plant.

Before leaf fall takes place, however, a colour change takes place. The green compound in the leaves known as chlorophyll is broken down and many of the useful constituent parts are ferried away into the main body of the tree. As this process takes place, other compounds in the leaves, previously masked by the intense green colouring, become more noticeable. The most common compounds are known as carotenoids, which are responsible for oranges and reds, and flavenoids which produce the yellow colourings. So far in my garden, about half the plants have changed colour. The foliage on the Azalea pontica has turned orangey- yellow, but it is the Japanese Maple, Acer Aconitifolium, fairly boring in early summer, which steals the show. The once-green leaves are a vibrant orange, stunning when backlit by the late afternoon sun.

Over the waterfall, I have trained a purple-leaved Acer Dissectum (Atropurpureum probably). So far, it has held on to its summer purple, but already there is a hint of bright red in evidence. In two weeks it will take centre stage, turning fire red to magnificent effect. Out in the wider world, the orangey-red maples in Victoria Park, Nelson, look magnificent now from the motorway, while horse chestnuts everywhere are turning light yellow.

I say everywhere, and you would expect the advance of autumn to be more advanced the further north you go. In these days of global warming we talk in terms of "climate", but climate itself can be local. Without doubt, Lancashire is a wet part of the country and we get more than our fair share of battleship-grey skies. Autumn nights draw in, but the impact of grey skies and pounding by rain bring on our autumn that little earlier than in some parts of the country.

Last weekend, I was on the moors north of Pickering. On the way through the Vale of Mowbray, the farmers were at work ploughing fairly dry fields, but it was on the supposedly exposed hills above Whitby I had my biggest surprise. Summer baskets still looked good outside the little stations along the Pickering-to-Grosmont railway, and the magnificent steam locomotive, Sir Nigel Gresley, looked wonderful in the surprisingly hot autumn sunshine. Rose hips were in abundance and rowan trees were laden with berries.

But the hydrangeas looked good too, still unmarked by autumn and in full flower. Fuchsias were still fantastic, covered in masses of flowers. Nearer the coast, the grass verges were dotted with little harebells, the odd orchid and most tree foliage was stubbornly green. In fact at Robin Hood's Bay, you could be forgiven for thinking we were still in August.

Just how hot it was, was brought home to me when I bought a gentleman's coat at a trade stand outside Goathland Station which was selling '40s fashions. GIs and Wrens were much in evidence, as were Waffen SS at Levisham, which for the weekend had been transformed to a town in wartime occupied France, and restyled Le Visham.

I lugged that coat for miles as we traipsed around from station to station and crawled from pub to pub, and heaved our bodies from cafe to cafe. For a while I even got the sun on my stubbornly white back, enjoying the late, almost Indian summer conditions. So why did I buy the coat? For winter of course, and in the present economic climate, the £5 price tag was another little ray of sunshine!