CLIMATE What is Climate? Climate is the average weather over a 30 year period for a specific region. It is the average pattern of weather for that region. Weather and climate is not the same thing. Weather is the short term state of the atmosphere and includes things such as temperature, precipitation (rain, hail and snow), air pressure and cloud cover. We watch a weather report on the TV. It is the daily or hourly change in atmospheric conditions. The weather can change every day because of wind and storms, as well as every season, because of the Earth s rotation around the sun. Calm Weather at Sea Stormy Weather at Sea So while the weather in an area changes every day, climate change can take hundreds or thousands of years. The Climate of South Africa South Africa is part of the Southern Hemisphere s subtropical zone. It has a wide variety of different climates in different regions but also has lower temperatures than other countries on the same latitude. Climate Regions The map overleaf shows the different climate regions of South Africa. Version 1: December 2013 Copyright My Cyberwall 2013 1
Subtropical Plateau This is a flat, elevated interior area, which is hot and dry with winter rain. Musina Area Version 1: December 2013 Copyright My Cyberwall 2013 2
Desert A desert is a region with very little or no rain. The desert region in South Africa is hot and dry. It is cool and foggy on the coast, for example Port Nolloth in Namaqualand. Mediterranean Climate This region has hot dry summers and cool rainy winters, for example, Cape Town. Port Nolloth Mediterranean Climate Cape Town Semi Arid Plateau This is an interior region with hot, rainy summers and cool dry winters. It is drier towards the west, for example, Upington. Semi Arid Plateau - Upington Version 1: December 2013 Copyright My Cyberwall 2013 3
Moderate Coast This region has mild weather with rain all year round, for example, Mossel Bay. Moderate Eastern Plateau Moderate Coast Mossel Bay This region has warm, rainy summers and cold, dry winters, for example, Johannesburg. It is hotter and drier further north. Subtropical Coast Moderate Eastern Plateau - Johannesburg This region is affected by the warm Agulhas current. It has hot, wet summers and warm, drier winters, for example, Durban. Subtropical Coast - Durban Version 1: December 2013 Copyright My Cyberwall 2013 4
Escarpment The escarpment is a steeply sloping area at the edge of a plateau. The climate is similar to the coastal region, but is colder because of the height. Subtropical Lowveld Escarpment Mountains The lowveld is a grassy, flat plain, which has hot, rainy summers and warm, dry winters, for example, Nelspruit. Subtropical Lowveld - Nelspruit Area Factors Affecting South Africa s Climate 1. Topography of South Africa The relief of a country or area has a major influence on the climate of that country/area. For more information you can return to the module: South Africa s Physical Map: http://www.mycyberwall.co.za/get-smart/geography/grade-5/physical-map-south-africa Hottentots Holland Mountains, Western Cape Version 1: December 2013 Copyright My Cyberwall 2013 5
2. Sea Currents The warm Mozambique current flows south west along South Africa s east coast, from the equator. The cold Benguela current flows north along the west coast from Antarctica. Air above a cold current is cold and there is little chance of rain. With a warm current, the air rises, condenses and then clouds and rain occurs. These factors strongly influence the climate. Sea Currents Clouds Forming Version 1: December 2013 Copyright My Cyberwall 2013 6
3. Distance from the Sea The sea has a moderating effect on climate. This means that areas that are close to the sea are not too hot in summer and not too cold in winter. The temperature margin (difference between the highest and lowest temperatures) is therefore small. The reason for this is that water masses are not heated as quickly as the land surfaces are. However, once water has absorbed heat, it retains it for longer than land surfaces. Sun on the Sea During the day, radiation of heat from the soil is high, but low at night. During the day, the radiation from the sea s water is less and this results in lower temperatures than in the case of the interior. At night, the sea cools off slower than the land and so coastal areas are warmer at night than the interior. 4. Temperature South Africa displays typical temperature patterns during different seasons. Few people plan a holiday on the west coast in winter, while Durban (east coast) has ideal holiday temperatures during winter. Thermometer Version 1: December 2013 Copyright My Cyberwall 2013 7
South Africa's temperature is influenced by the following: 1. Latitude Location The further a region is located from the equator (0º), the colder it is. Places in the tropics therefore experience warmer temperatures than places at the poles. Version 1: December 2013 Copyright My Cyberwall 2013 8
2. Altitude The higher above sea level, the colder it becomes. Temperature therefore drops as altitude increases. Because the interior plateau is located high above sea level, it will be colder there than along lower coastal areas. Frost is common on the interior plateau and snow occurs on the high mountains. Temperature Falls at Higher Altitude Mount Kilamanjaro. Kenya (5 895m) Temperature is usually shown on a line graph and rainfall on a bar graph. However, sometimes they are combined onto one graph, using one type of scale, as per the examples below. Cape Town Climate Graph South Africa Climate graph contributed by climatetemp.info Version 1: December 2013 Copyright My Cyberwall 2013 9
Johannesburg Climate Graph Durban Climate Graph Johannesburg Climate graph contributed by climatetemp.info Durban Climate graph contributed by climatetemp.info Version 1: December 2013 Copyright My Cyberwall 2013 10
Kimberly Climate Graph Port Elizabeth Climate Graph Kimberley Climate graph contributed by climatetemp.info Port Elizabeth Climate graph contributed by climatetemp.info Version 1: December 2013 Copyright My Cyberwall 2013 11
Pretoria Climate Graph Pretoria Climategraph contributed by climatetemp.info Version 1: December 2013 Copyright My Cyberwall 2013 12