Climate of Zambia
Encyclopedia
The climate
of Zambia
in Central
and Southern Africa
is tropical modified by altitude (elevation)
. In the Köppen climate classification
, most of the country is classified as humid subtropical or tropical wet and dry, with small patches of semi-arid steppe climate in the south-west.
Climate and specifically rainfall amount is the chief determinant of type and distribution of the ecoregions of Zambia
.
(May to October/November), corresponding to winter. The dry season is subdivided into the cool dry season (May to August), and the hot dry season (September to October/November). The modifying influence of altitude gives the country pleasant subtropical weather rather than tropical conditions for most of the year.
The average tempature in Zambia in the winter (more colder season) is 125oF and in the summer it can get as low as 5oF.
The rains are brought by the Intertropical Convergence Zone
(ITCZ) and are characterised by thunderstorm
s, occasionally severe, with much lightning
and sometimes hail. The ITCZ is located north of Zambia in the dry season. It moves southwards in the second half of the year, and northwards in the first half of the year. In some years, it moves south of Zambia, leading to a "little dry season" in the north of the country for three or four weeks in December.
The highest rainfall is in the north, especially the north-west and the north-east, decreasing towards the south; the driest areas are in the far south west and the Luangwa River
and middle Zambezi River valleys, parts of which are considered semi-arid. None of the country is considered arid
or to be desert
.
Flooding is an annual event on floodplains, to which people and wildlife are adapted. Flash floods after unusually heavy rain cause damage when they occur in places that do not experience annual floods. Erosion and the washing out of roads and bridges are common. Crops are frequently damaged by flooding and hail. Too much rain when the maize
crop is flowering, or late in the season when it should be drying off prior to harvest can be very damaging and promotes rotting of stored grain.
s which have waxy leaf cuticle
s for the same purpose. The deciduous trees usually produce fresh green or reddish leaves just before the rainy season. Grasses and some other herbaceous plants dry up above ground but regenerate quickly with the onset of rains from roots and tubers, etc.
Except for those living in areas of permanent freshwater, animals are adapted to the long dry season, as seen in migration and breeding patterns.
gardens; or by lightning in the early rainy season. Because such fires happen annually, there is no great build up of dry fuel in the bush, and so the fires are not usually devastating. They may kill animals, and damage crops if the rains end early and fires happen before harvest. The presence of fire-adapted plants and palaeoecological studies indicate that such fires have happened for millennia.
s (grasslands which become marsh
y in the rainy season) are prevalent in most of the country and water is usually available in them from spring
s or shallow well
s. Dambos also release groundwater to streams and rivers towards the end of the dry season, keeping them flowing permanently. Small earth dam
s are often constructed in dambos as a source of water and as fishponds.
For the human population, the location of rural settlements is determined by access to water in the dry season (though borehole
s are now commonly used to augment supplies). Traditionally, people have also migrated
in the drier areas where rivers dambos are not prevalent. In Barotseland
, people move with their livestock, grazing them on the Barotse Floodplain
in the dry season and moving to higher ground at the margins during the rainy season.
The ability to grow enough food in the rainy season to last the long dry season is also a factor in population distribution. Traditionally some communities have divided the year into farming in the rainy season, and fishing and hunting in the dry season, when herbivores can be found more easily as they visit sources of water, and fires can be set to expose them or drive them into traps.
on which Zambia is located, typically between 1000 and 1300 m (3,280.8 and 4,265.1 ft), modifies temperatures, which are lower than for coastal areas at the same latitude
, and pleasant for much of the year. On the plateau (covering about 80% of the country) temperature ranges, depending on location are:
Most of the country is frost-free but in some years ground frost
occurs. This is restricted to the highest exposed hills, or more widely in the lower humidity areas of the southernmost parts of the country.
Temperatures are higher at lower elevations, such as the Luapula
-Mweru
and Mweru Wantipa
/Tanganyika
valleys in the north, and highest in the lower Luangwa and Zambezi valleys in the south, typically experiencing 40 °C (104 °F) in October, with rising humidity making for uncomfortable conditions.
During the rainy season months of November to April or May some days may be humid, but daily maximum temperatures are usually a little lower than in the hot dry season. The rain can be cooling, unlike in the humid tropics.
In the rainy season, winds are localised with thunderstorms and may be destructive but usually confined to small areas, such as blowing roofs off buildings. The country does not suffer tornado
es or cyclone
s of widespread destructive force.
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
of Zambia
Zambia
Zambia , officially the Republic of Zambia, is a landlocked country in Southern Africa. The neighbouring countries are the Democratic Republic of the Congo to the north, Tanzania to the north-east, Malawi to the east, Mozambique, Zimbabwe, Botswana and Namibia to the south, and Angola to the west....
in Central
Central Africa
Central Africa is a core region of the African continent which includes Burundi, the Central African Republic, Chad, the Democratic Republic of the Congo, and Rwanda....
and Southern Africa
Southern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
is tropical modified by altitude (elevation)
Elevation
The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....
. In the Köppen climate classification
Köppen climate classification
The Köppen climate classification is one of the most widely used climate classification systems. It was first published by Crimea German climatologist Wladimir Köppen in 1884, with several later modifications by Köppen himself, notably in 1918 and 1936...
, most of the country is classified as humid subtropical or tropical wet and dry, with small patches of semi-arid steppe climate in the south-west.
Climate and specifically rainfall amount is the chief determinant of type and distribution of the ecoregions of Zambia
Ecoregions of Zambia
The biomes and ecoregions in the ecology of Zambia are described, listed and mapped here, following the World Wildlife Fund's Global 200 classification scheme for terrestrial ecoregions, and the WWF freshwater bioregion classification for rivers, lakes and wetlands.Zambia is in the Afrotropic...
.
Seasons
There are two main seasons, the rainy season (November to April) corresponding to summer, and the dry seasonDry season
The dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year...
(May to October/November), corresponding to winter. The dry season is subdivided into the cool dry season (May to August), and the hot dry season (September to October/November). The modifying influence of altitude gives the country pleasant subtropical weather rather than tropical conditions for most of the year.
Rainy season
Rainfall varies over a range of 500 to 1400 mm (19.7 to 55.1 in) per year (most areas fall into the range 700 to 1200 mm (27.6 to 47.2 in)). The distinction between rainy and dry seasons is marked, with no rain at all falling in June, July and August. Much of the economic, cultural and social life of the country is dominated by the onset and end of the rainy season, and the amount of rain it brings. Failure of the rains causes famine from time to time.The average tempature in Zambia in the winter (more colder season) is 125oF and in the summer it can get as low as 5oF.
The rains are brought by the Intertropical Convergence Zone
Intertropical Convergence Zone
The Intertropical Convergence Zone , known by sailors as The Doldrums, is the area encircling the earth near the equator where winds originating in the northern and southern hemispheres come together....
(ITCZ) and are characterised by thunderstorm
Thunderstorm
A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the...
s, occasionally severe, with much lightning
Lightning
Lightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...
and sometimes hail. The ITCZ is located north of Zambia in the dry season. It moves southwards in the second half of the year, and northwards in the first half of the year. In some years, it moves south of Zambia, leading to a "little dry season" in the north of the country for three or four weeks in December.
The highest rainfall is in the north, especially the north-west and the north-east, decreasing towards the south; the driest areas are in the far south west and the Luangwa River
Luangwa River
The Luangwa River is one of the major tributaries of the Zambezi River, and one of the four biggest rivers of Zambia. The river generally floods in the rainy season and then falls considerably in the dry season...
and middle Zambezi River valleys, parts of which are considered semi-arid. None of the country is considered arid
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
or to be desert
Desert
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...
.
Flooding is an annual event on floodplains, to which people and wildlife are adapted. Flash floods after unusually heavy rain cause damage when they occur in places that do not experience annual floods. Erosion and the washing out of roads and bridges are common. Crops are frequently damaged by flooding and hail. Too much rain when the maize
Maize
Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...
crop is flowering, or late in the season when it should be drying off prior to harvest can be very damaging and promotes rotting of stored grain.
Plant and animal adaptations
Deciduous trees which lose leaves in the dry season to conserve water predominate over evergreenEvergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
s which have waxy leaf cuticle
Plant cuticle
Plant cuticles are a protective waxy covering produced only by the epidermal cells of leaves, young shoots and all other aerial plant organs without periderm...
s for the same purpose. The deciduous trees usually produce fresh green or reddish leaves just before the rainy season. Grasses and some other herbaceous plants dry up above ground but regenerate quickly with the onset of rains from roots and tubers, etc.
Except for those living in areas of permanent freshwater, animals are adapted to the long dry season, as seen in migration and breeding patterns.
Bushfires
In the middle to late dry season, bushfires are prevalent, and smoke is noticeable by smell and as a haze. The fires are ignited by villagers hunting, burning crop residue, and preparing chitemeneShifting cultivation
Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned. This system often involves clearing of a piece of land followed by several years of wood harvesting or farming, until the soil loses fertility...
gardens; or by lightning in the early rainy season. Because such fires happen annually, there is no great build up of dry fuel in the bush, and so the fires are not usually devastating. They may kill animals, and damage crops if the rains end early and fires happen before harvest. The presence of fire-adapted plants and palaeoecological studies indicate that such fires have happened for millennia.
Water sources in the dry season
Most rivers, lakes and swamps, except in the far south and south-west, are permanent. In addition, damboDambo
Dambo is a word used for a class of complex shallow wetlands in central, southern and eastern Africa, particularly in Zambia and Zimbabwe. They are generally found in higher rainfall flat plateau areas, and have river-like branching forms which may be nowhere very large, but common enough to add up...
s (grasslands which become marsh
Marsh
In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....
y in the rainy season) are prevalent in most of the country and water is usually available in them from spring
Spring (hydrosphere)
A spring—also known as a rising or resurgence—is a component of the hydrosphere. Specifically, it is any natural situation where water flows to the surface of the earth from underground...
s or shallow well
Water well
A water well is an excavation or structure created in the ground by digging, driving, boring or drilling to access groundwater in underground aquifers. The well water is drawn by an electric submersible pump, a trash pump, a vertical turbine pump, a handpump or a mechanical pump...
s. Dambos also release groundwater to streams and rivers towards the end of the dry season, keeping them flowing permanently. Small earth dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
s are often constructed in dambos as a source of water and as fishponds.
For the human population, the location of rural settlements is determined by access to water in the dry season (though borehole
Borehole
A borehole is the generalized term for any narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water or other liquid or gases , as part of a geotechnical investigation, environmental site...
s are now commonly used to augment supplies). Traditionally, people have also migrated
Transhumance
Transhumance is the seasonal movement of people with their livestock between fixed summer and winter pastures. In montane regions it implies movement between higher pastures in summer and to lower valleys in winter. Herders have a permanent home, typically in valleys. Only the herds travel, with...
in the drier areas where rivers dambos are not prevalent. In Barotseland
Barotseland
Barotseland is a region in the western part of Zambia, and is the homeland of the Lozi people or Barotse who were previously known as Luyi or Aluyi. Its heartland is the Barotse Floodplain on the upper Zambezi River, also known as Bulozi or Lyondo, but it includes the surrounding higher ground of...
, people move with their livestock, grazing them on the Barotse Floodplain
Barotse Floodplain
The Barotse Floodplain also known as the Bulozi Plain, Lyondo or the Zambezi Floodplain is one of Africa's great wetlands, on the Zambezi River in the Western Province of Zambia...
in the dry season and moving to higher ground at the margins during the rainy season.
The ability to grow enough food in the rainy season to last the long dry season is also a factor in population distribution. Traditionally some communities have divided the year into farming in the rainy season, and fishing and hunting in the dry season, when herbivores can be found more easily as they visit sources of water, and fires can be set to expose them or drive them into traps.
Temperature
The elevation of the great plateauAfrican superswell
The African superswell is an extraordinary uplift of the African continent, particularly its southern half; southern Africa on average lies a full kilometer above sea level, with seemingly anomalous uplifts extending well into the south Atlantic ocean....
on which Zambia is located, typically between 1000 and 1300 m (3,280.8 and 4,265.1 ft), modifies temperatures, which are lower than for coastal areas at the same latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
, and pleasant for much of the year. On the plateau (covering about 80% of the country) temperature ranges, depending on location are:
| Months | Season | Mean Daily Maximum °C (°F) | Mean Daily Minimum °C (°F) |
|---|---|---|---|
| May-August | Cool and Dry | 21-26 (70-79) | 6-12 (43-54) |
| September-October | Hot and Dry | 28-35 (82-95) | 17-22 (63-72) |
| November-April | Rainy | 25-30 (77-86) | 14-19 (57-66) |
Most of the country is frost-free but in some years ground frost
Frost
Frost is the solid deposition of water vapor from saturated air. It is formed when solid surfaces are cooled to below the dew point of the adjacent air as well as below the freezing point of water. Frost crystals' size differ depending on time and water vapour available. Frost is also usually...
occurs. This is restricted to the highest exposed hills, or more widely in the lower humidity areas of the southernmost parts of the country.
Temperatures are higher at lower elevations, such as the Luapula
Luapula River
The Luapula River is a section of Africa's second-longest river, the Congo. It is a transnational river forming for nearly all its length part of the border between Zambia and the DR Congo...
-Mweru
Lake Mweru
Lake Mweru is a freshwater lake on the longest arm of Africa's second-longest river, the Congo. Located on the border between Zambia and Democratic Republic of the Congo, it makes up 110 km of the total length of the Congo, lying between its Luapula River and Luvua River segments.Mweru...
and Mweru Wantipa
Lake Mweru Wantipa
Lake Mweru Wantipa is a lake and swamp system in the Northern Province of Zambia. It has been regarded in the past as something of mystery, displaying fluctuations in water level and salinity which were not entirely explained by variation in rainfall levels; it has been known to dry out almost...
/Tanganyika
Lake Tanganyika
Lake Tanganyika is an African Great Lake. It is estimated to be the second largest freshwater lake in the world by volume, and the second deepest, after Lake Baikal in Siberia; it is also the world's longest freshwater lake...
valleys in the north, and highest in the lower Luangwa and Zambezi valleys in the south, typically experiencing 40 °C (104 °F) in October, with rising humidity making for uncomfortable conditions.
During the rainy season months of November to April or May some days may be humid, but daily maximum temperatures are usually a little lower than in the hot dry season. The rain can be cooling, unlike in the humid tropics.
Wind
Prevailing winds in the dry season are generally moderate but occasionally more severe and may bring cool dust-laden air from distant arid regions. Whirlwinds are very common but not usually destructive; waterspouts can be seen over lakes.In the rainy season, winds are localised with thunderstorms and may be destructive but usually confined to small areas, such as blowing roofs off buildings. The country does not suffer tornado
Tornado
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone, although the word cyclone is used in meteorology in a wider...
es or cyclone
Cyclone
In meteorology, a cyclone is an area of closed, circular fluid motion rotating in the same direction as the Earth. This is usually characterized by inward spiraling winds that rotate anticlockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth. Most large-scale...
s of widespread destructive force.