Tropical hot desert occurs mainly on the western side of the continents along the tropic of Cancer and the tropic of Capricorn. The annual average temperature is around 38 degrees C. The day temperature may rise to 50 degrees C, and the night temperature may fall to 10 degrees C. This causes high variation in the daily temperature. The rainfall is very scanty. Most parts of the deserts are barren and full of sand dunes.