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Kenya

Kenya Climate

Kenya Climate
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Best time to visit

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When to go

Best time to visit is either June through to mid October, or early December through to end March. The long rains start end of March and run through to the end of May. Northern Kenya sees most of its heavy in rain during the short rains in November. The wildebeest migration is active between July and October. The coastal areas are best visited between August and end March.

Kenya Climate

Overview

Kenya is located in East Africa. Bordered by Somalia, Ethiopia, South Sudan, Uganda, and Tanzania, it possesses an extensive coastline, is home to a large section of the Rift Valley, and – for the purposes of understanding when and where best to travel – is normally divided into 4 climatic zones: mountain, highland, arid and coast.

The weather in Kenya is determined by its tropical location, by its proximity to the Indian Ocean, its topography and the oscillating effects of the Inter-tropical Convergence Zone (ITCZ), which annually travels back and forth across equatorial Africa, providing Kenya with a bimodal annual rainfall pattern: the long rains occur from March through to May, the short rains from October to December. Humid, warm, the rainy seasons

The climatic zones can be further sub-divided, with arid composed of semi arid, arid and very arid, the highlands from plains to foothills, all of which has a localised affect on the climate, and therefore on the flora and fauna found there. Furthermore, some areas west of the Rift Valley experience one long rainy season.

Generally speaking, the north, north-east and east of Kenya is arid, most of it very, while much of central Kenya, some of the mid south borderlands, the coastal hinterlands and the coast proper north of Malindi are semi-arid. The arid and very arid areas constitute 65% of Kenya, and have an annual average rainfall of between 200 and 600mm and annual temperatures range from 23°C to 34°C. Semi-arid areas are higher (900 to 1800m), experience an average annual rainfall of 500 to 1000mm, and are slightly cooler. Known collectively as the ASALs, the semi arid, arid and very arid regions contain the majority of Kenya’s wildlife areas, and are consequently vital to the country’s economy.

The remaining climatic zones occupy 20% of Kenya. The coastal climatic zone, a band some 10 miles wide, extends from the Tanzanian border to Malindi, is humid all year round, experiences an average rainfall level of between 1000 and 1250mm and an average annual temperature range of 22°C to 30°C. The central and western highlands and parts of the central Rift Valley areas are Kenya’s most temperate zones. Here, the altitudinal range is 900 – 4000m; annual rainfall levels average out at between 950 and 3000mm and average annual temperatures range from 14°C to 28°C. Finally, mountainous zones are restricted to Mt Kenya and Mt Elgon and their immediate environments.

The best times, then, for viewing wildlife run from late December to late February and mid June to late September, these months being dry, the cover diminished, the game that much easier to see. This is true of most of Kenya, except the Lake Victoria basin, where there is a single dry season, running from October through to March. This said, the wet season is not – wildlife speaking – a non-starter: while it is less easy to spot, the game is in very good shape during this period; it is also when many species calve, when behaviour changes, allowing for specialist interest; and it is the time for watching birds.

However… Kenya is proving vulnerable to climatic change. Annual rainfall patterns are becoming less easy to predict, with both drought and unseasonable rains affecting everything from agricultural output to the movement of wildlife. Previous to the 1970s, Kenya experienced droughtevery 10 years. Since then the pattern has changed, with the ratio of drought years to normal years increasing exponentially between 1970 and 2011.* The direct and indirect effect on wildlife is substantial. In Amboseli, for example, the 2006 to 2009 drought killed off migratory herbivores in large numbers, with wildebeest suffering losses of up to 95%. The knock-on effects – on predator numbers – were (and remain) a real concern, as does the fact that local communities’ domestic animal losses put further pressure on wild habitats, with a rise in the need for bush meat and charcoal.

Traditional thinking prioritises the ASALs as being particularly vulnerable to climate change. They are. However, longitudinal studies bear witness to their resilience, with both flora and fauna fluctuating in response to change. Right now, the greater threat would seem to be the fact that wild species are reliant on habitats and migratory corridors guaranteed by the will of their host communities. These communities are especially badly hit by climate change. In this respect, sustainable tourism and creative conservation strategies would seem to represent the best way forward, as low impact, responsible travel adds to the economic wealth of the areas, has a negligible effect on the environment and aids conservation packages.

*During the 1970s the pattern contracted, and droughts began to appear once every 7 years. In the 1980s it contracted further, with droughts occurring once every 5 year. In the 1990s, the rains failed once every 2 to 3 years. And – since 2000 – the country has had more drought years than it has had normal ones.

South and Eastern Kenya

South and eastern Kenya includes the borderlands south of Nairobi, the majority of the land either side of the Nairobi – Mombasa road, and is bordered on its eastern flank by the coastal strip and in the north by the Tana River. From a wildlife point of view, the area is home – in the south – to Lakes Magadi and Natron, the Nguruman escarpment, the Shampole Conservancy, Amboseli, the Chyulu Hills and Tsavo West, and – in the east – to Tsavo East, South Kitui and the Tana River Primate Reserve. In addition to these public wildlife sanctuaries, a number of Masaai owned ranches guarantee vital migratory corridors.

Bisected by the Nairobi -Mombasa road, the area is either arid or very arid. Generally speaking, the further east and south one gets, the drier and hotter the climate. So, just out of Nairobi, in Athi River, the annual average temperature is 20°C, the average annual rainfall 744mm. Here, April is the wettest month, with an average yearly rainfall of 157mm, with May and November close behind. Maximum average temperatures rarely exceed 26°C. Contrast these figures with, first, those of Shampole, just 120 km south of Nairobi, with temperatures in the thirties and an annual rainfall level of 479mm, and to those of Amboseli, where annual rainfall figures rarely exceed 300mm, and temperatures are only slightly lower than those of Shampole.

The effect of a dry, hot climate on the area’s flora depends also on permanent water sources, and on local topographical influences. Thus, while it is true to say that as you descend south or south-east out of Nairobi, the country is characterised by a series of semi-arid to very arid habitats, by Acacia woodlands, bush, scrub and, finally, in areas like Garissa, desert, there are areas whose position – altitude or proximity to a permanent water source – makes for an ecosystems all of their own. Chief among these are the south Rift Valley’s the Nguruman escarpment, the Chyulu Hills, Taita Hills, Amboseli and the Tana River, all of which contribute to the area’s occasional anomalies – montane grasslands and forest (the Nguruman and the Chyulu Hills) swamp (Shampole and Amboseli, for example) or riverine forest (the Tana River, for example). Much of the area sits on Yatta Plateau, the world’s longest lava flow, and is served by the saline lakes Magadi and Natron and by a number of hot springs, salt licks and smaller volcanic lakes.

The movement of animals in the area is dictated by the weather. The dry season – January to March and May to September – is best for viewing animals, with large numbers of herbivores and carnivores congregating about permanent water sources. Wildlife is generally dispersed and – due to increased cover – harder to spot during the wet season, the long rains occurring from March through to May, the short rains from October to December. Our main south-east Kenyan destinations – the Shampole Conservancy, Amboseli, the Chyulu Hills and the Taita-Tavita district – are all part of the same Amboseli biosphere, with Amboseli as its core, surrounding areas a buffer zone, and zonal border lands acting as transition zones. Seasonal migratory herbivores include wildebeest, elephants and zebra, while resident herbivores include buffalo and impala, with carnivores such as lion, hyena and cheetah prepared to travel when necessary.

Central Highlands

The Central Highlands are located north of Nairobi. Bound in the east by the Thika-Meru road and in the west by the Siracho escarpment, they finish just beyond the town of Maralal. From the point of view of safari, the main areas of interest are the Laikipia plateau, the Aberdares and Mt Kenya.

Intensively farmed, the land immediately north of Nairobi goes from gum tree and pineapple plantations to coffee until – after Nyeri – it is increasingly characterised by a mix of small holdings, ranches, and by the Aberdare uplands and the foothills of Mt Kenya. As altitudes increase, so the land is less cultivated, with rain and bamboo forests dominating, before giving way to moorland. Altitudes go from 1,500m to just under 4000m. Average rainfall levels range from Nairobi’s 790mm to 2000mm in the Aberdares and low lying regions of Mt Kenya. Between Nairobi and Nyeri, average annual temperatures are fairly constant, ranging from 16°C and 19°C.* Beyond here, the northern half of the Central Highlands – collectively known as the Laikipia – becomes an enormous interconnected and increasingly arid patchwork of ranches. Average annual rainfall levels decrease the further one travels north, with Kisima receiving 440mm, and temperatures increase to an average of around 22°C.

The range of climates in the Central Highlands makes for a fascinating range of flora and fauna. While known more for its flora – and its importance as a natural water tower – the Aberdares is home to 40 species of animal, with low numbers of lion, elephant, buffalo, rhino and leopard present. Mountainous forest specialists include the melanistic black leopard and the eastern bongo, a forest antelope usually found between 3000 and 4000m. As with much of the rest of the country, January to March and late June through to October is when it is dry, and animals tend to congregate around permanent water sources. However, given the altitudinal range of the Aberdares, and the more permanent cover available, wildlife here is less easy to spot than it is in the plains. During the wet season (March through to May and from October to December), the animals disperse across the area, are very difficult to see, and wildlife viewing – at this time in the Aberdares – becomes much more the preserve of scientists than of travellers. Night time temperatures can drop below 10°C.

The Laikipia is an altogether different proposition. Moving north from a vegetation characterised by moorlands and rainforest through an area of cultivation and into savannah and acacia, it falls gradually – from an altitude of 2000m to 1,700m – and becomes increasingly dry, with an average annual rainfall range of between 700mm and 450mm. In terms of surface water, its only permanent source is the Ewaso Ngiro River, which flows north before curving east into Samburu. Very dry between January to March and late June through to October, wildlife congregates in the riverine habitats along Ewaso Ngiro, and around the waterholes found throughout the Laikipia. A valuable and – conservation-wise – important fauna and flora resource, the Laikipia is vulnerable to pressure from burgeoning human settlements, an early indication of which was had in 2009, when over-irrigation in its upper reaches caused a drought affected Ewaso Ngiro to run dry.

*Please be advised that these figures do not include Mt Kenya proper.

Central Rift Valley

The Rift Valley proper runs from the northern shores of Lake Turkana to Lake Magadi, on the Kenyan-Tanzanian border. However, it falls into different climatic zones, its northern half and southern tip both decidedly arid (see South and eastern Kenya and Northern Kenya for climate details), its lower midsection ranging from temperate to semi arid.

This section, then, refers to the lakes of Naivasha, Elementaita, Nakuru, Bogoria and Baringo.

Largely semi-arid, Naivasha receives an average of 650mm of rain per year, with just April managing to break into the hundreds. At 1884m, it is reasonably elevated, and annual temperatures hover about the 17.2°C mark. Closer to the equator (than its sister lakes), Naivasha follows a bimodal rainfall pattern common to much of the country, with the long rains occurring in March to May and the short rains in October to December. During this time, while temporary water sources are well stocked, the wildlife is dispersed across the lake basin and difficult to spot. However, during the dry season, which runs from January to March and then May to September, the wildlife – giraffe, several species of gazelle and antelope, hyrax, zebra, small carnivores, including hyena, jackal and serval – concentrates about the lake, and around nearby Crater Lake.

The remainder of the section is slightly different in that it drops down to an altitude of about 1025m, and while Nakuru’s average annual temperature is also 17°C, both Bagoria and Baringo average out at around 25°C. More, the pattern precipitation changes: while still bimodal, it is only June that separates one set of rains from the other, making March through to September feel like one long wet season – much in keeping, therefore, with annual rainfall patterns found to the west, around Lake Victoria. In view of this, wildlife in these areas is dispersed between March and September, and much easier to spot from September through to March.

Western Kenya (Masai Mara)

Western Kenya is not just the Mara. It is also Lake Victoria and its surrounding environs, Kakamega Forest, Mt Elgon, Saiwa Swamp and Ruma National Park. However, for the purposes of understanding the effects of climate on the behaviour of animals, we will be speaking mainly of the Mara Triangle, which is situated in the Trans Mara District in south-west Kenya, along the Kenyan-Tanzanian border.

The migration is a weather driven phenomenon. A damp, plains habitat, the Mara Triangle is watered by the Mara River and its tributary, the Talek River. An elevation of between 1500 and 2180m, an average annual daytime temperature range of 21°C and 26°C and an average annual rainfall of 1400mm. The pattern of precipitation is classically bimodal, with the long rains March to the end of May and the short rains October to December. In this respect, the Mara differs from much of the rest of western Kenya which, under the influence of Lake Victoria and possibly the Congo airstream, experiences a single rainy season – from March to September.

Depending on the rains, the migration can arrive in the Mara any time between July and early September, taking advantage of standing water and fresh grass supplies. It will remain for the duration of the short rains, before moving south in November. The area boasts healthy numbers of resident populations, all which are best viewed in the dry season – January to March and June to September.

Northern Kenya

Northern Kenya proper consists of just over a third of the country. North of Marala, Isiolo and Garissa, it includes Turkana, Samburu, the Matthew Mountains, Meru, Mt Nyiru, the Chalbi Desert, and the Shaba Game Reserve.

Save the forested mountain zones – the Matthews Mountains, Mt Nyiru, Mt Kulal, Mt Marsabit and the Ndoto Mountains – and the localised riverine habitats along the Kerio and Ewaso Ngiro rivers, much of northern Kenya is arid to very arid to desert. Altitudinal ranges in the south and along the north-west are in the early thousands, while around and to the east of Lake Turkana, they drop to below 1000m.

Average daytime temperatures in the northern plains range between 20°C and 26°C – though, in some places and certain times of the year, averages are more likely to be in the early thirties, with exceptional zones – the Chalbi desert and Hedad plains, for example – rising into the late forties. Mountain temperatures average out at between 17°C and 19°C.

The pattern of precipitation is nominally bimodal, with the long rains occurring between March and May, the short rains in October and November. Nominally because local trends and the area’s susceptibility to drought combine to make nonsense out of long term predictions: the short rains, for example, fail entirely around Lake Turkana, and are experienced only in November in other areas, while the 2006 to 2009 drought saw the likes of Samburu experience little or no rainfall, month in month out. The picture changes in the mountains, which, known as sky islands, are microclimates unto themselves, and here the pattern is strictly bimodal, with peaks in April and November. Thus, average rainfall levels range between 100mm and 150mm in the Chalbi desert, rise to between 200mm and 300mm in much of the north-east, to between 300mm and 500mm in the south and along the north-west, while the mountains receive anything between 1000mm and 1200mm.

In terms of the climate affecting the movement of animals, the Samburu area and the northern edge of the Laikipia have been especially badly hit by drought, with the rains in April 2009 failing entirely and the Ewaso Ngiro all but running dry. In a normal year, the best time for viewing animals would be the dry season, in December to March and May to September, but the area’s unpredictable climate continues to throw up anomalies. The last big drought broke in late 2009 and there were floods in Samburu in 2010, but – except for sporadic rains in November 2010 and February 2011 – the river is once again dry. The immediate effect, of course, is that animals congregate around the few remaining water sources, carnivores flourish and the viewing is exceptional. However, as the drought sets in, so animals must move or die.

Clearly, journeying further north is hardy travelling indeed, with just the Matthews Mountains and the riverine habitats along the Kerio River offering anything like a traditional wildlife experience. Here, dry season boundaries – June to early October and December to early March – are very distinct and represent the time best for viewing gazelle, oryx, ostrich, elephant, leopard, lion, forest hog and even wild dog. Elsewhere, the major attraction is scenery and culture, with Lake Turkana, the Chalbi Desert and Mt Nyiru being our three main destinations. Like the Matthews, Mt Nyiru is very pleasant most of the year, but wet in April and November. Rain has little effect on travel in northern Turkana and the Chalbi, though April through to August is relatively cooler.

The Coast

Kenya’s coastal strip extends from the Tanzanian border south of Gazi to the Kenyan-Somali border in the north.

With a climatic zone 10 miles wide, the coastal weather system is influenced by the Kaskazi and Kuzi monsoons. The first of these, the Kaskazi blows in from the north-east during the months of November to March inclusive. Reasonably benign, these relatively dry winds, though warm, help mitigate the effects of an otherwise very humid atmosphere. The second monsoon, the Kuzi, lasts from April through to September, and brings with it the long rains, which last from April through to June, with May being the year’s wettest month. The short rains, though present, are less significant, and occur between October and November.

While slightly drier in the north, rainfall all along the coast is reasonably constant, with Lamu experiencing an annual average of 800mm, Malindi – a third of the way down – around 1050mm and Mombasa coming in at 1160mm. In the coast hinterlands – west of the belt – the picture is markedly different, drier, less predictable, and more subject to the Inter-tropical Convergence Zone (ITCZ) than it is the Kuzi monsoon winds (see South and eastern Kenya). May to September is the windiest period, March and November the calmest.

The average annual temperature throughout is 26°C, though it is not unusual during the months of December, January and February to experience temperatures of up to 30°C.

In terms of visiting the coast, the period between late November and early March is the hottest, calmest, and it is when the sea is at its clearest. This said, and apart from April and May, when it is wet, the rest of the year is also relatively fine, with the short rains limiting themselves to short late afternoon and night time downpours. For snorkling, diving and swimming, late November through to March is best, when the sea is clearer, while fishing depends on type – marlin arrive in the last week of November, with the Kaskazi monsoon, and the tuna season is September through to October.*

*For further information with regards to fishing the Pemba Channel, go to http://www.bigame.com/kenya_fishing_statistics.htm