Why is the Namib Desert considered a cool coastal desert?

The Namib Desert is classified as a cool coastal desert primarily due to the influence of the Benguela Current, an oceanic current that flows northward along the Atlantic coast of southern Africa.12

This current brings about the upwelling of cold water from the depths of the ocean. As air flows off these adjacent cold coastal waters, it is significantly cooled, resulting in monthly mean temperatures (15–21 °C or 59–70 °F) that are much lower than what would typically be expected for the desert's latitude.13

While this cooling effect keeps the region's temperatures relatively low, it also contributes to the desert's extreme aridity. The cool air has a low moisture content and inhibits the formation of typical rain-bearing sea breezes. Instead, the interaction between the cold current and the atmosphere frequently produces fog and low-level clouds, which serve as a vital, albeit scarce, source of moisture for the desert's unique ecosystem.1345