Climate in Africa and the World
Senior 3 · Geography
Climate in Africa and the World
Lesson 3 of 4
25 min
Let's begin
Manaus in the Amazon and Resolute in the Canadian Arctic are both official weather stations, but their yearly averages are 42.5 °C apart: 27.4 °C in Manaus, −15.1 °C in Resolute. Africa has no place like Resolute, and no place like Moscow, with its months of frozen winter. To complete the picture, this lesson looks at the four broad climatic zones of the other continents named in your syllabus: tropical, temperate, arctic and mountain.
Figure 4. Climate graphs from four zones. Drawn by Ganzaa from WMO data.
Tropical climates lie roughly between the tropics. As in Africa, they range from equatorial (the Amazon Basin, much of South-East Asia) through tropical wet-and-dry (the Brazilian Highlands, northern Australia) to monsoon climates, where a wind that reverses with the seasons brings a very wet summer, as in India. Manaus (3°S) is typical of the Amazon: 26.6–28.6 °C all year and 2,362 mm of rain, with a drier spell from July to September.
Temperate climates lie in the middle latitudes, between about 35° and 60°, where there are four seasons: a warm summer and a cool or cold winter.
Beyond about 66° the sun is low or absent for months. The tundra climate has a short, cool summer in which only the top of the soil thaws; the ice-cap climate of Antarctica and Greenland never warms above freezing. Resolute (75°N) averages −32.1 °C in February and only 4.8 °C in July, and receives only 164 mm of precipitation: polar regions are cold deserts.
On high mountains, climate changes with height rather than latitude (unit 2): it is colder, windier and often wetter on windward slopes. Säntis, a summit station at 2,501 m in the Swiss Alps, averages −0.7 °C over the year and receives 2,840 mm of precipitation, much of it as snow. In the tropics, the highest African peaks have their own small "arctic" zones near their summits.
Figure 5. Climate graph of Säntis, a mountain station. Drawn by Ganzaa from WMO data.
Definition
Continentality: the effect of distance from the sea on climate. Inland places have hotter summers, colder winters and so a larger annual range than coastal places at the same latitude.
Monsoon: a seasonal reversal of the winds that brings a very wet season, e.g. the summer monsoon of South Asia.
Worked example
Worked example 1: continentality. London (51.5°N) and Moscow (55.8°N) are at similar latitudes. Compare their annual ranges and explain the difference.
Answer: the difference is caused mainly by continentality.
Worked example
Worked example 2: comparing with Africa. Which of the four zones has no lowland example in Africa, and why?
The arctic zone and the cold-winter continental type of the temperate zone. Africa stretches only from about 37°N to 35°S, so no lowland part of it is far enough from the Equator for long freezing winters. Only the summits of Kilimanjaro, Mount Kenya and the Rwenzori are cold enough for snow and ice.
Warning
Read negative temperatures carefully. When a range crosses 0 °C, subtract the negative number: Moscow's range is , not .
Tip
Four questions to place any climate graph: Is every month above 18 °C (tropical)? Is it very dry (desert)? Is there a cold winter below 0 °C (continental or arctic)? Is the summer above 10 °C (if not, arctic or high mountain)?
Practice
Sources and credits
Figures 4 and 5, the worked examples and the practice exercises are written by Ganzaa.
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
