A semi-arid climate or steppe climate describes climatic regions that receive precipitation below potential evapotranspiration, but not extremely. A more precise definition is given by the Köppen climate classification that treats steppe climates (BSk and BSh) as intermediates between desert climates (BW) and humid climates in ecological characteristics and agricultural potential. Semi-arid climates tend to support short or scrubby vegetation, with semi-arid areas usually being dominated by either grasses or shrubs.

To determine if a location has a semi-arid climate, the precipitation threshold must first be determined. Finding the precipitation threshold (in millimeters) involves first multiplying the average annual temperature in °C by 20, then adding 280 if 70% or more of the total precipitation is in the high-sun half of the year (April through September in the Northern Hemisphere, or October through March in the Southern), or 140 if 30%–70% of the total precipitation is received during the applicable period, or 0 if less than 30% of the total precipitation is so received. If the area's annual precipitation is less than the threshold but more than half the threshold, it is classified as a BS (steppe climate).

The Turkana are a Nilotic people native to the Turkana District in northwest Kenya, a semi-arid climate region bordering Lake Turkana in the east, Pokot, Rendille and Samburu to the south, Uganda to the west, and Sudan and Ethiopia to the north. They refer to their land as Turkan.

According to the 2009 Kenyan census, Turkana number 855,399, or 2.5% of the Kenyan population, making Turkana the third largest Nilotic ethnic group in Kenya, after the Kalenjin and the Luo, slightly more numerous than the Maasai, and the tenth largest ethnicity in all of Kenya. Although this figure was initially controversial and rejected as too large by Planning Minister Wycliffe Oparanya, a court ruling (Feb 7, 2012) by Justice Mohammed Warsame stated that the Kenyan government accepts the 2009 census figures for Turkana.

The language of the Turkana, an Eastern Nilotic language, is also called Turkana; their own name for it is ŋaTurkana or aŋajep a ŋaTurkana.

The Turkana people call themselves ŋiTurkana (The Turkana). The name means the people of Turkan. They are mainly semi-nomadic pastoralists.