The temperature divide

Why does Wales get a mixture of temperatures?

In Wales the two main influences on the temperature are the sun and the sea. To understand what these do, let's take a look at some maps.

Britain's summertime temperature patterns

This map of Britain shows that in summer you need to go south to get warm. The north of Scotland has holiday temperatures that can go below 13°C, but in the south they are over 17°C (of course these are averages so it can get hotter and colder than this!).


Summertime temperature patterns

Let's take a look at Wales. The map shows that South East Wales is a warm place to be with temperatures over 16°C, but the rest of Wales is cooler with the northern tip of Anglesey under 15°C.


Welsh Summer temperature patterns

So, what causes these differences in temperature patterns? Let's take a look at the diagram to get some clues.


Sun Rays and the Atmosphere

As you can see, the diagram shows what happens when the sun's rays enter Earth’s atmosphere and strike the surface. Its journey through the atmosphere is longer at Point A, and shorter at Point B. The longer the journey, the less heat gets to the ground and the cooler the place will be. The long journey north of the UK is warmed up less than the short journey south.

Also, the sun's rays will be spread out at a low angle in the north and concentrated from above more in the south. This explains why it is warmer in the south and colder in the north during the UK’s summertime.

Point B is located on the line of the equator and as the atmosphere is thinner, the sun's rays are spread over a larger area than at point A. This happens because light travels in straight lines, but then hits the Earth which is round.

Wintertime temperature patterns

This map shows a different trend! In winter it is colder in the east, sometimes below 4 °C and warmer in the west, sometimes over 7°C.


Winter temperature patterns

Why are temperatures different in these areas?

To the west of Wales and the UK is the Atlantic Ocean. During the winter, the Atlantic acts as a giant hot water bottle and helps keep western areas warm. To the east of the UK is a large continental area (Europe and Asia) separated by just a narrow sea. Continents cool down rapidly and the centre of Europe and Russia often drops below minus 20°C in the winter. This acts like a freezer with the door left open which chills the east of the UK.

Even worse, if air from the continent moves over us, it picks up moisture as it passes over the North Sea and then drops it on us as snow. This is what happened in the winter of 2010 when many schools in Wales were shut down because of the snow, but even more in Eastern England were shut down.


Snow Day

How do these temperature differences affect people?


Sun and Snow

Temperatures have a big impact on many economic activities, like farming and tourism. In West Wales warmer winter temperatures mean that the growing season starts early so farmers can make extra money by planting early season new potatoes and salad crops. In the east the colder winters mean that crops start growing later in the year. But, on the other hand, the hot eastern summers are perfect for ripening crops.

This year, 2010, has produced a bumper harvest, up by five per cent on 2009, for UK wheat farmers thanks to the warmer weather. Also, in February and March 2010 the Aviemore Ski resort in Scotland had the deepest and longest lasting snow, and the best skiing conditions for decades!

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Draw maps or diagrams to explain the differences in the UK's temperature between summer and winter.
How do you think these temperature patterns might affect you?

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