The Climate

 

Arrakis is a very hot and arid planet, characterized by extreme heat and lack of surface moisture. The temperature, for the majority of the planet, ranges anywhere from below-zero temperatures at night, to around 28 degrees celsius and above during the day, remaining consistent until one reaches either poles, where the temperature becomes more moderate. There is little variation of weather or temperature due to seasons, as Arrakis has almost no tilt on its axis.

 

The atmosphere is roughly similar to that of Earth, mostly nitrogen with about a quarter of the air made up of oxygen and a few additional trace gasses, allowing human life to exist without environmental suits.

 

Surface water is near unheard of, and precipitation is rare outside of the ring of mountains located at the northern pole. Said precipitation, along with the scant amount of polar ice, makes the northern pole the center of Arrakeen society.

 

Large amounts of the surface, however, are covered in very salt heavy plains, leading some to believe that Arrakis may have at one point had liquid water on the surface.

 

Due to the thin surface sand that covers the planet, monumental sandstorms sweep across the planet, making surface living impossible without the natural protection of the polar mountain ranges, or the subterranean caves utilized by the Bedouin-like tribes of nomads that can be found outside of the polar cities, known as Fremen.

 

The Fremen take an active part in regulating the climate of their planet, engaged in a centuries long plan of natural terraforming involving growing shrubs and collecting water in vast underground cisterns, in the hope of someday turning the planet from a vast desert into a temperate paradise.

 

The reason for Arrakis' extreme heat is hard to pinpoint. At a glance, it has several traits of a terrestial planet not unlike Earth, even taking up a similar place in the order of planets. However, due to the singular, light coloration of the planet's surface, the temperature should be rather lower than that of Earth. However, there is good reason to believe that Arrakis' atmosphere contains a large amount of greenhouse gasses that cause it to be so warm.