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| Wednesday November 25, 2009 | Accessibility help | Text only | Print | Send to a friend | Make this my homepage | Contact Us | Help |
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British Weather (Part One) |
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It is a national pastime for many of us to talk, and largely moan about, British weather. Weather is often the initial topic in any conversation.
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There is a reason for this national obsession, in that our weather is very changeable, influenced largely by the unsettling effect of low-pressure zones moving in with the prevailing westerly and south-westerly winds from the Atlantic. However, there are many reasons why instead of complaining about the weather - or blaming it on the forecaster - we should be thankful for the climate that prevails on our shores. ...our weather is greatly influenced by the seas around us...
Ours is part of a temperate climate, which is characterised by rainfall all year round, and a relatively small fluctuation in temperatures. The British Isles are in a maritime temperate zone, that is to say our weather is greatly influenced by the seas around us, which keep Summer temperatures relatively cool but at the same time prevent very cold weather in winter.
This is because unlike the land, the sea takes a comparatively long time to heat up and cool down. So after a Summer of warm weather the seas around the British Isles retain warmth throughout much of the winter which helps to temper the impact of cold winds and cold air masses approaching us. On the other hand, when spring and early summer arrive, the sea has cooled down and thus can be quite cold in May and June even though the weather may be warm and sunny. So any breezes coming off the sea will have a correspondingly cooling effect on the temperatures we feel. ...areas well away from the coast will be noticeably warmer than those on the coast.
This is particularly true on the east coast of Great Britain with the waters of the cool, shallow North Sea. On a warm Summer's day the air over the land is warmed, causing it to rise. To replace it the colder air over the sea moves in - the start of a sea breeze - which has the effect of reducing the temperature. However, this sea breeze is unlikely to extend right inland, so areas well away from the coast will be noticeably warmer than those on the coast.
Another unseen factor on our temperatures, especially in winter, is the Gulf Stream (or North Atlantic Drift) which brings warm waters across the ocean. These waters bathe our west coasts, keeping temperatures higher and reducing the chances of frost in winter for these coastal areas. It is significant that some of our coldest waters during winter are off the coast of Norfolk, which does not benefit from the effects of the Gulf Stream. Some of the warmest waters are off the coast of Cornwall where the sea might be a respectable 10°C (50°F) in winter, only 6°C (11°F) below the Summer average. All in all the seas around us, as well as being a useful protection against would-be invaders, are a good natural defence against extremes of very cold weather. Despite this, and even in a small area like the British Isles, there can still be quite large variations in climate. For example, on average Cambridge has something like a dozen days a year when the temperature will reach 25°C (77°F), whereas Lerwick in the Shetland Isles can sometimes go a full 12 months without registering as high as 18°C (64°F). | |||||
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