The African climate is driven by the Sun’s annual North-South movement.

The perpendicular sun rays give maximum heat to earth’s surface, which creates a global band of instability called Inter Tropical Convergence Zone (ITCZ). Due to uneven land-ocean distribution and their heating properties the ITCZ is not a line, parallel to the Equator, but is bent and widened toward bigger land masses. Ocean currents additionally distort the picture, creating warmer and colder seas. Despite being at the same latitude, Mozambique is green due to its warm sea while Namibia is desert because of its cold sea.

World oceans are much bigger than continents and are the main players in airmass formation. The equatorial part of Indian Ocean forms a distinct ITCZ with its typical easterly trade winds. They invade Africa directly, feeding it with moisture and rain.

In summer, ITCZ travels quite North and part of equatorial Easterly trade winds turn and become South-West winds along Somali coast. Later they become the classic Indian monsoons which feed India and Himalaya’s heat low pressure zones.

The prevailing summer Southerly winds in Africa feed the ITCZ over Sahel, causing regular rains in Kenya, Ethiopia, South Sudan and Central Africa. The mountainous Ethiopia is much more unstable than surrounding lowlands. The rains there precede the arrival of ITCZ arrival and last longer. The clouds in east Africa are beautiful but with low cloud bases.

In winter, the Middle East and Himalayan mountains cool down and feed the ITCZ which has moved south. These drier North-Easterly winds come from Iran, Pakistan and India and prevail over Somalia, Ethiopia and Kenya. The warm Arabian sea adds some low-level moisture, but at higher levels atmosphere stays dry and stable, thunderstorms are rare. Cloud bases, close to the coast, are not very high, but 2-300 km inland and in mountain regions they reach 3-4000+ meters a.m.s.l. Thermals are 3-4 m/s strong, well-formed and periodically triggered.

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The winter North-Easterly winds start after November’s rainy season and finish before April’s rains, when ITCZ passes Kenya twice. Their peak is in February.

The North-Easterlies penetrate easily through East and North Kenyan arid lowlands, but further inland they meet obstacles like the 5,000 meters Mt. Kenya, Mt. Aberdare (3,500 m), Eldored plateau (2,000) and Rift Valley channeling effects. On the opposite South-West side of Kenya, lake Victoria’s breeze stops the North Easterly and forms a regular convergence line, which keeps Serengeti and Masai Mara green.

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Naivasha area is the most interesting paragliding cross-country arena of Kenya. The famous Kerio Valley with its record breaking Out-and-Return flights is limited to soaring and thermalling the same ridge all the time. The strong Easterly winds there are also turbulent at midday. The other open parts of Kenya are limited to downwind flying.

Naivasha arena is special, because its sheltered by the 3,500 meters high and 80 km long Abardere mountain range, which effectively blocks the North-Easterly and creates powerful convergences behind. This is also the highest part of Kenyan Rift Valley’s bottom with lake Nakuru, Elementaita and Naivasha being at 2,000 m. The Rift Valley itself is 30-40 km wide, nesting the spectacular volcano craters of Mt. Longonot, Mt. Suswa, Ebury, Gilgil and Nakuru. The hot springs of Hell’s Gate National park and the wild life conservation zones give a unique pre-historic spirit.

Naivasha paragliding arena stretches from Nakuru, where the North Easterly are channeled as Northerly winds by Rift Valley, to Mt.Suswa volcano crater where Rift Valley turns south and descents towards lake Magadi and Natron. North-East of Naivasha there are several terraces and a plateau before the 3,500 meters Aberdare mountain range. South-West of Naivasha is the 3,000 meters opposite bank of Rift Valley. The usual crossing routes are around Naivasha lake, along the volcanic areas of Gilgil – Eburu and along Kijabe-Longonot-Hell’s gate hills.

In winter season, at about 2-3 pm strong North-Easterly winds come from Nairobi area, so avoid flying near the lee side of North-East bank of Rift valley (Kijabe and Mai Mahiu). The middle of Rift Valley and South-West bank are fine. Despite the afternoon invasion of North-Easterly in Kijabe and Longonot area, the other side of Navasha lake, Eburu and Gilgil stay sheltered by Aberdere mountain. The Northerlies which come from Nakuru also stop the South-Easterlies near Naivasha.

 

 

Naivasha’s part of Rift Valley has a specific micro climate. Cloud bases are distinctively higher (4K) than those on the other side of Nairobi (3K). One reason is that the bottom of Rift Valley near Naivasha is quite high – 2000 m. Another reason is that the lower arid parts of Rift Valley further North and further South, beyond Mt. Suswa and Nakuru, provide long lasting supply of warm air. A third reason is that the surrounding 3,500 m Aberdere mountain and 3000 m highlands lift up the whole airmass and improve the wind gradient. Few hundred meters below cloud base it becomes significantly colder. Cloud suck and rapid congestus cloud formations are common, but they don’t develop further into thunderstorms because in winter season there are drier air and mild inversions at high altitudes.

Naivasha lake is relatively big (15 km). There is often a blue hole, even when surrounding highlands overdevelop vertically and horizontally. The lake produces sea breeze with mild shear turbulence, which spreads 5-10 km away. The lake can work as a conductor of strong winds and gust fronts.

The biggest challenge for Naivasha’s premium flying site – Kijabe is the strong North-East wind, which floods Rift Valley in the afternoon. Kijabe take off window depends on the general strength of the North-Easterly, but also on the humidity (sheltering wind gradient effect) and atmospheric instability (stronger thermals and clouds stop or slow down the prevailing wind). Even the driest and windiest February has many take off windows for Kijabe, giving classic cross-country flights like:

• Kijabe-Naivasha-Nakuru-Naivasha
• Kijabe-Longonot volcano-Eburu-Naivasha (clockwise around Naivasha lake)
• Kijabe-Naivasha-Eburu (counter clockwise around Naivasha lake)
• Kijabe-Longonot volcano-Suswa volcano-Narok-Masai Mara