The Climate of Britain
9.1 Introduction
Britain is in the temperate climate zone and does not have extremes of temperature or rainfall. The Gulf Stream, a large Atlantic Ocean current of warm water from the Gulf of Mexico, keeps winters quite mild whilst during summertime, warm but not excessively hot temperatures are experienced. The average annual temperature in Britain is about 10ºC, with the summer average temperature being around 15ºC and the winter average being around 5ºC (day and night). As we have seen in previous sections, the British weather is dominated by frontal depressions which form in the Mid-Atlantic and pass across into Europe, bringing changeable weather.
9.2 Air Masses
The main air masses that affect Britain are those that form over the Mid-Atlantic but there are several other air masses that bring particular weather conditions. The air masses are defined according to where they originated and their course of travel. For example air from Arctic regions is classified as Arctic maritime as it originates in the Arctic and travels across the North Sea. Another example is Tropical maritime air which originates near the Gulf of Mexico and travels across the warm Atlantic Ocean before arriving in Britain. Other air masses include the Polar maritime, Polar continental and Tropical continental. Examples of air masses which affect British weather are shown on the diagram below.
9.3 Maritime climates
Most of the airflow across Britain throughout a year is maritime, including tropical and polar air masses. Tropical maritime air is mild in winter and warm and humid in summer. If these air masses are associated with frontal depressions, there is usually plenty or rainfall, but when associated with anticyclones, settled weather with warm sunny spells occurs.
Polar maritime air masses usually result in cool, showery weather throughout the seasons but may bring snow during the winter months.
9.4 Continental climates
Polar continental air in winter is very cold. The air mass is usually dry and stable but as it passes over part of the North Sea, sufficient heat and moisture can lead to the formation of showers, often snow, over eastern England and Scotland. 
During summer, the polar air mass brings warm air as even northern parts of Europe experience high temperatures during the summer months.
Tropical continental air reaches Britain from the Saharan region of Africa. It gives dry weather in the summer and also gives pleasantly warm weather in the winter.
9.5 Geographical variation in the British climate
The general patterns of climate experienced in Britain have been identified. However, there are also noticeable differences that occur throughout Britain. The coldest winter temperatures in Britain occur in eastern Scotland and England. The western side of Britain is warmed by the influence of the tropical maritime airstream. Temperatures are therefore colder in the east than in the west during winter. During summer the south is warmer than the north. This is due to the differences in solar heat received, being greater in the south.
The British climate can be divided into four parts as shown on the map below. The northwest section is characterised by mild winters and cool summers and the northeast with cold winters and cool summers. The southwest experiences mild winters and warm summers and the southeast with cold winters and warm summers. Western parts of Britain generally experience a more maritime climate during winter whilst eastern Britain is influenced by the cold airstreams from the European continent. In summer, climate differences are more dominated by latitude.
Precipitation also varies throughout Britain. Western Britain, particularly the parts on higher ground, receives considerable rainfall. Most of this is frontal rainfall but there is also relief rainfall due to the mountains such as the Lake District and the Welsh Mountains. Parts of Scotland can receive over 250 cm or 100 inches of precipitation per year. Eastern Britain, particularly southeastern parts, receive much less rainfall. Areas of the southeast may receive only 50 cm or 20 inches of precipitation per year. Much of eastern Britain lies in the rain shadow of hills and mountains such as the Lake District, the Peak District and the Scottish Highlands.
EXERCISES
- Label the map below with the correct climate summary for each part of Britain.
Cool summers
Warm Summers
Mild winters
Cold winters
Cool summers
Warm Summers
Mild winters
Cold winters
- Some of the words below are mixed up. See if you can unscramble them.
Britain is in the merteatpe .............. climate noze .......... British eatwher ............... is dominated by frontal piodressens ..................... which give changeable weather. The Gulf remSat ........... Drift causes western Britain to have ldmi ........ winters. Eastern Britain has lerdoc............. winters which are influenced by continental air masses. In mumers............ the south of Britain is warmer than the north due to higher levels of lrsoa.......... heat in the south.
- Below is some climate data for several cities in Britain. Plot graphs of the data, using a computer package if possible, to show the variation in temperature and rainfall for each site.
Site
Month
J
F
M
A
M
J
J
A
S
O
N
D
A
Temp ºC
5.9
8.9
8.3
8.1
13.3
14.5
15.9
16.3
13.7
9.8
5.2
4.7
Rain mm
84
7
84
99
35
97
28
14
60
112
48
72
B
Temp ºC
4.9
8.3
7.3
6.4
10.9
12.7
14.4
14.8
12.8
8.4
5.2
4.8
Rain mm
99
41
46
84
85
76
101
48
42
124
81
53
C
Temp ºC
7.1
8.1
8.8
8.5
14.2
14.3
15.5
16.0
15.0
10.3
7.0
6.2
Rain mm
128
17
89
77
30
73
53
23
100
145
84
138
The average monthly rainfall and temperatures for the three sites above are:
Site
Reading Annual average
A
Temperature ºC
10.4
Rainfall total mm
740
B
Temperature ºC
9.2
Rainfall total mm
880
C
Temperature ºC
10.9
Rainfall total mm
957
Using your knowledge of climate variation throughout Britain, which location do you think each set of data belongs to. Mark the map with A, B, C next to the site you think they represent. Write a few lines to explain your choice.
