BRITAIN’S WEATHER
The British Isles lie in the temperate latitude of mainly westerly winds where depressions (areas
of low pressure) and their associated fronts (bands of cloud and rain) move eastwards across the
North Atlantic bringing with them unsettled and windy weather, particularly in winter.
Between the depressions there are often small anticyclones (areas of high pressure) which bring a
welcome period of fair weather. This sequence of depressions and anticyclones is responsible for
our notoriously changeable weather.
WEST AND NORTHERN BRITAIN
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
Tend to lie close to the path of Atlantic depressions and so have mild and stormy winters,
cool and windy summers.
Mountainous areas have high rainfall amounts.
SOUTHERN AND EASTERN BRITAIN
 Lowland areas have a drier climate with a wider range of temperature than the north and
west
 Winters are not as severe as those on the continent because of the warming influence of
the North Atlantic Drift.
TEMPERATURE
Daily variation
On a daily basis, the temperature is usually lower
at night than by day, with the minimum
temperature usually occurring shortly after dawn
and the maximum temperature often 2 or 3 hours
after midday.
In urban areas maximum and minimum
temperatures tend to be higher than in rural
areas. This is because buildings store heat and
because heat is released as a result of industrial
and domestic energy consumption.
Seasonal variation
The temperature varies according to the season
because the axis of the Earth is tilted in relation
to the Sun. January is, on average, the coldest
month and July the warmest.
Average UK daily minimum temperature January
In winter the main factor influencing
temperature differences is distance from the coast, particularly the west coast.
Source: WeatherFile (Nelson Thornes and Met.Office)
TASKS
Look at the temperature map above.
1.
Which of the following areas has on average the lowest winter temperatures.
a. South-west England
b. Central Ireland
c. East Anglia
d. Central-Northern England
e. Northern Scotland
f. Central-Southern Scotland
2.
Why do you think that these two places have the lowest temperatures in winter?
In summer the main factor influencing temperature
is distance from the equator.
In addition coastal areas are less warm than inland
areas as the sea is much colder than the land.
3. Which of the following areas has on average
the highest summer temperatures in the UK?
a. Northern Scotland
b. Northern Ireland
c. Central England
d. Northern England
e. South-Eastern England
f. Wales
4. Why do you think that these places have the
highest temperatures in summer?
SUNSHINE
Average UK maximum temperature July
Since the length of day varies from winter to summer, the duration of sunshine shows a marked
seasonal variation. As a result, December is, on average, the month with least sunshine and June is
the sunniest.
In general, sunshine duration decreases with altitude and increasing latitude, although aspect also
plays an important part – south-facing slopes receive more sunshine than those facing north.
Over the year as a whole, the sunniest places are flat areas near the coast.
5. What is aspect?
6. Why are south-facing slopes likely to be warmer than slopes facing other directions?
Source: WeatherFile (Nelson Thornes and Met.Office)
7.
Why are flat places sunnier than hilly or sloping places?
8.
Where do the prevailing (most frequent) winds that affect the British Isles come from?
9.
What effect does the coast, in particular the
west coast, have on temperatures in:
a. January?
b. July?
10. How and why do temperatures in urban areas
differ from those in rural areas?
11. Which parts of the British Isles have:
a. Most and;
b. Least sunshine?
12. Where in the British Isles is rainfall highest?
Suggest at least 2 reasons why it is so high
there.
RAINFALL
Average daily maximum sunshine duration (hrs)
The average rainfall in the Uk varies enormously from about 5000mm p.a. in the Western Highlands
of Scotland to about 500 mm in parts of East Anglia and South-East England. Overall the wettest
areas are in the western half of the country. This is because:


They are nearest to the normal path of rainbearing depressions
The most mountainous parts of the British isles are in the west and relief rainfall occurs
here.
The south-eastern parts of the country have low rainfall because they are further away from the
normal track of the depressions. However, much of the Midlands, north-east England and eastern
Scotland also have low rainfall because they are in a rainshadow.
In summer, rainfall is often of a showery nature and is normally more intense than the winter
rainfall associated with fronts and depressions. The heaviest falls of rain, during summer
thunderstorms, can produce rainfall rates of more than 100mm per hour.
Source: WeatherFile (Nelson Thornes and Met.Office)