Exfoliation is a weathering process associated with hot, arid regions. It is a mechanical weathering process that involves the peeling off of the outer layer of rocks in sheets or layers due to extreme temperature changes. In hot and arid regions, rocks experience intense heating during the day and rapid cooling at night, leading to the expansion and contraction of the outer layer of the rocks. Over time, this process causes the outer layer to weaken and eventually crack and peel off, resulting in the exfoliation of the rock surface. This process is also known as onion skin weathering due to its resemblance to the peeling of onion layers. Examples of areas with exfoliation include deserts such as the Sahara and the Mojave Desert.