NO WONDER we talk about the weather a lot. Perhaps Saharan tribes have other social niceties, but here it isn't just a way of getting talking, it really matters. Especially if you're on holiday. Whatever the brave face tourists put on, the Cornwall they've come to see isn't the one we're used to. The promise which lures them down the A30 is hot sand and clear water, sunsets over the northern horizon, cool beer, surf, stars, moorland walks, barbecues, bright mornings, the clarity of the air, open boats in the blue of the bay. One mild depression and that lovely bubble deflates, leaving lines of unwilling pilgrims pouring into entertainment venues and towns too small to hold them before going back to their accommodation for evenings of Boggle and Scrabble while trying to dry their clothes. We've all been there. It's no comfort to explain that such weather is what makes Cornwall what it is.

But it's true.

The default wind direction is a flow from west to east across miles of ocean, enriching the air with a high proportion of moisture. This is why our air feels soft and our winters are mild and almost frost-free, but there is a penalty when the air hits Cornwall's granite walls. Then, even on a fine day it can balloon up to a colder altitude and immediately condense into cloud or mist, just enough to keep the land in its shadow dull and grey. Certain headlands carry an infuriating legacy of a long tail of cloud which doesn't shift all day even when the surrounding areas are baking in the sun.

When a depression drags the wind over the water the clouds come along with it, bearing sweeping drizzle or heavy showers or, on horrible summer days, both. Locals are used to this, used to rain lashing on one side of the house only, sea which is more often grey than blue, dripping trees and sloshy puddles. We're kitted out for it, and anyway we're not supposed to be enjoying ourselves.

But the rain is Cornwalls' saving grace. Except for the lush valleys Cornwall is a hard environment for growing things. The soil is thin, acid and clayey, not deep and fertile like eastern England, and all exposed areas are scoured by a queue of winter gales. In a drought Cornwall dries up fast, the granite bones soon peeping through the green face. But drought, thank goodness, is rarely our lot. When hosepipe bans and even stand-pipes vex the home counties we can nearly always rely on another hydroponic lifeline from the Atlantic. This won't be much consolation to those whose bored children are steaming up the car's rear windows or those looking for a tan to take home along with the souvenirs, and it really isn't fair. In a well-ordered world everyone should have at least a few fine holiday days. But Cornwall is blessed with water around it, in it, and on it, and always will be.