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Kenya

State of the Climate Kenya 2022

Attachments

1. Introduction

1.1. General weather and climate features of the Country

The climate of Kenya is highly variable both in time and space. Just like the rest of the East African region and other parts of the tropics, Kenya is prone to climate extremes such as floods, landslides, and droughts (Muhindi et al 2001: Liebmann et al., 2014; Philippon et al., 2015; Uhe et al., 2017; Funk et al., 2018; Kilavi et al., 2018). In the last decade alone, the frequency and severity of climate extremes is increasingly evident as global warming and climate change continue to be experienced across many parts of the world (IPCC, 2021: Lott et al. 2013; Holden et al 2022).

Kenya is located in Eastern Africa between latitudes 5o North and 5o South and between longitudes 34o East and 42o East. It borders Ethiopia in the North, Somali in the East, Tanzania in the South and Uganda in the West. Its total land area is about 569,137 km2. Generally, its agro-climatic characteristics vary between arid and semi-arid in the Northwest, Eastern and some parts of the South-east regions and semi-humid to humid in central, western, and some parts of the coastal region. Rainfall in Kenya is seasonal and follows a bimodal distribution pattern.

The “long rains'' season occurs from March to May (MAM) and the “short rains” season from October to December (OND (Fig 1.1)). However, the coastal region, the highlands west of the Rift Valley and the Lake Victoria Basin experience a third rainfall season between June and August (JJA). The long-rains season is regarded as the most important for agricultural production in Kenya and contributes to 26% of the Gross Domestic Product (GDP) and an additional 27% of GDP from indirect linkages with other sectors. The agriculture sector in Kenya employs more than 40% of the total population and more than 70% of the rural population (ASTGS, 2019).

Various other sectors depend on the weather for their optimum functioning. The performance of the tourism sector, which is a main foreign exchange earner for Kenya, is influenced by rainfall and temperature fluctuations. Health, sanitation, and human settlements are likewise impacted by changes in weather and climate and even more so as climate changes. The energy and transport sectors are directly impacted by weather. For example, temperature fluctuations and severity of extreme weather events – such as heavy rains resulting in floods – damages energy and transport infrastructure. These impacts influence the risk of delays, disruptions, damage, and failure across land-based, air, and marine transportation systems. The impact of drought on hydro-generated electricity is also well understood in Kenya.

The main driver of weather and climate conditions in Kenya is the bi-annual northward and southward movement of the overhead sun across the equator. The movement of the overhead sun influences the position of the Inter-Tropical Convergence Zone (ITCZ) (Muhindi et al 2001). Other important drivers include the El Nino Southern Oscillation, Indian Ocean Dipole and the Congo Basin Air mass among others. According to the annual rainfall distribution patterns, the climatology of Kenya can broadly be defined as indicated in Figure 1.2.

The counties in the highlands west of the Rift Valley receive the highest rainfall amounts annually of more than 1800mm, a few other counties in the central highlands east of the Rift Valley likewise receive high annual rainfall amounts.

Counties that receive the lowest annual rainfall amounts are generally arid or semi-arid ones which include those in Northwest and Northeast Kenya.

The temperature patterns in Kenya are highly variable in time and space, with the highest temperatures ranging from 35oC to 40oC occurring in Northwestern and Northeastern regions during the months of January to March, while the months of June to August are characterized by cooler temperatures in most parts of the country. The lowest temperatures (ranging from 3oC - 6oC) are observed in central regions of Kenya particularly, Nyahururu.

With regard to wind, the Northwest of the country (Marsabit and Turkana counties), the edges of the Rift Valley, as well as the coastal area, enjoy fairly good wind speeds and have the potential to be successfully exploited for energy generation (Kazimierczuk, 2019). Based on analysis of station data, the surface wind patterns in Kenya range from moderate to strong southeasterly winds, especially over the eastern and northern parts of the country during the months of May, June, July and August. The rest of the year experiences relatively calm winds bringing in moisture or dry air, depending on the season.

For the evaluation of the state of the climate for 2022, 32 stations across the country with full rainfall data and 30 stations with full maximum and minimum temperature data were used.