Global Distributions of Climate

The climate in a place is the average of its weather conditions.

The climate varies across the world depending on the following four factors;

• Latitude
• Altitude
• Distance from the sea
• Prevailing winds

Latitude

• The closer an area is to the equator, the hotter the area will be.
• This is because the direct rays from the sun are concentrated along the equator.

Altitude

• Temperature decreases the higher we travel into the atmosphere.
• The higher a place is above the sea level, the colder it is likely to be.

Distance from the sea

• In the summer, the sea heats up less quickly than the land so places further inland will have hotter summers.
• In the winter, the sea heats up more quickly than the land so people on the coast will have warmer winters.

Prevailing winds

• If the wind blows from the direction of the equator, then it is likely to be warm.
• If the wind blows from either of the poles then it is likely to be cold.

UK Climate

Explanation of the patterns of temperature and precipitation are given below for the UK. The climate of the UK is described as having mild, wet winters and warm, wet summers. It is called a temperate maritime climate.

Temperate means that the UK does not feel the heat from the tropics or the cold from the poles. Maritimes means that the UK feels the influence of the sea.

The sea reduces the temperature of differences between the summer and winter and increases the amount of precipitation.

Understanding Climate Graphs

Climate graphs show the temperature and precipitation levels for each month of the year in a specific place.

To describe the temperature of a place (the red line), it is best to state the highest and lowest temperatures and name the month.

You can then work out the average range of temperature by subtracting the lowest number from the highest.

To describe the precipitation levels of a place (the blue bars), it is best to state the highest and lowest precipitation and name the month.

Climate Zones

There are six major climate zones located throughout the world.

Equatorial

Lying between the Tropic of Cancer in the Northern Hemisphere and the Tropic of Capricorn in the south, equatorial climates are home to most of the world’s rainforests where rainfall and humidity are high. Temperatures are not that extreme — generally 25 to 35 °C — with not much variation through the year.

Arid

Deserts are found mainly across the subtropical continents. Here, descending air forms large, almost permanent, areas of high pressure leading to cloud-free skies virtually all year round. Annual rainfall is low and, in some deserts, almost non-existent. Because they’re so dry, the temperature range in deserts is huge, regularly exceeding 45 °C by day in summer and often falling to below freezing overnight in winter.

Mediterranean

The hot, dry summers of the Mediterranean, South Africa and southern Australia are caused by a seasonal shift of the descending air that also creates our deserts. Low summer rainfall is matched by many months of warm, sunny weather. But, at times, dangerously hot spells of weather engulf these regions with fiercely high temperatures of up to 45 °C. In winter, there is more rain and cooler temperatures, but little frost.

Snow

In the higher northern latitudes, the vast forests of fir and spruce (often called the taiga) and the featureless tundra endure long, hard winters with short, bountiful summers, separated by rapid seasonal changes during spring and autumn. In the northernmost regions, the land is permanently frozen and will not thaw even during the brief summer.

Polar

The Arctic is mostly frozen ocean, and while its climate is moderated by the relatively warm waters of the Atlantic Ocean, winter temperatures can still fall to below -30 °C. Antarctica is a vast continent of mountains and high plateaux buried under more than 3 km of ice. Temperatures below -80 °C have been recorded and the Antarctic i nterior is very dry — drier than many deserts. This is because as the temperature falls so does the atmosphere’s capacity to hold water vapour needed to make snow.

Temperate

This classification covers a range of climates from Mediterranean-type climates and humid, subtropical zones to maritime climates influenced by the oceans — like ours in the UK. The UK has a typical maritime climate, where temperatures are quite moderate although hot summer days and cold winter nights still occur. Summers in maritime climates can be hot, warm or cool. In the UK we have what’s considered to be a warm summer, whereas in Iceland the season is classified as cool.