Or, more precisely, the distance between the ground and the center of the eyeball. But assuming the earth were a perfect sphere: Average radius of earth = 6,372,797 meters Draw a circle representing the earth.
As a result, the Namib receives an average annual rainfall of only 2.5cm (1in). The sand dunes of the desert receive moisture from the atmosphere, in the form of fog. Every 10 days or so, a dense night fog rolls inland for a distance of 80km (50mi) or more, shrouding the coast and much of the desert. The fog condenses into a thick dew, creating an annual average of 4cm (1.6in) of moisture. Temperature in the Namib reaches a high of 66Â°C (150Â°F) in the middle of the day. Gravel and rock plains extend north from the Kuiseb River. The treacherous coastal waters of this region regularly snare ships, such as the Dunedin Star (1942) and the Shawnee (1976), and cast them up on the shifting sands.
High desert areas typically have the greatest diurnal temperature variations. Low lying, humid areas typically have the least. This explains why an area like the Snake River Plain can have high temperatures of 38 Â°C (100 Â°F) during a summer day, and then have lows of 5â10 Â°C (41â50 Â°F).t the same time, Washington D.C. , which is much more humid, has temperature variations of only 8 Â°C (14 Â°F); urban Hong Kong has a diurnal temperature range of little more than 4 Â°C (7 Â°F).