Weather Wise

Did you see the wind-speed arrows on yesterday's weather map? They seemed to be in a state of great confusion. In the north (or the "top" of the map, as we amateur meteorologists call it), everything looked in order. There was a 28mph wind blowing southwards down the west coast ("left-hand side") of Scotland and a 25mph north wind blowing down the east coast.

Just above Northern Ireland, however, the wind veered towards England to become north-westerly, then turned into a pure westerly down the west coast of England from the Midlands to the south-west.

On the east, however, from the south coast to just north of East Anglia, we had a south-westerly wind of between 22 and 25mph. Britain, in essence, was being treated like the ball in a game of celestial blow-football, with players on three of our four sides all trying to blow us in different directions.

All this is caused mainly by three low-pressure areas that have chased each other across the Atlantic, with two of them ending in a dead-heat almost directly above this country. Near the centre of a depression, winds may flurry in various directions, making them a less useful guide than usual to the progress of the weather.

Generally, however, the wind is a good guide to weather over the British Isles. Here is what you should expect for various wind directions:

Westerly: usually brings depressions across the country; mild temperatures but heavy rain in winter, cool and cloudy in summer.

Northerly: Cold at any time, with snow and sleet in winter.

North-westerly: Changeable, generally cool, but often bright and dry in the south.

Easterly: Warm in winter, cold in winter, often very cold in the south and east, with snow and sleet. East winds bring the driest summers to the west of the country.

Southerly: Warm and thundery in summer, but in winter it may be mild and damp (if associated with a low in the Atlantic), or cold and dry (if associated with a high in central Europe).

South-westerly: mild and wet in winter; warm and possibly rainy in summer.

Finally, if there's an area of high pressure above us, we can expect it to bring warm, dry weather in summer, with a chance of thunderstorms, but in winter it will be cold and frosty, with morning fog. A low-pressure area, by contrast, will generally bring unsettled conditions, with strong winds and again a chance of storms.