Why does semi arid climate exist?

Semi-arid climates exist due to a combination of geographical and meteorological factors. These regions typically receive limited rainfall, often between 10 to 20 inches annually, due to their location in the rain shadow of mountain ranges or far from moisture sources like oceans. Additionally, high evaporation rates and temperature variations can further limit moisture availability, leading to dry conditions. As a result, semi-arid areas often support grasslands or scrub vegetation rather than dense forests.