Most of the arid surface of Geonosis consists of hills, plateaus, and great rocky outcroppings. For most species, life on the planet is extremely difficult. Because the planet's magnetic field is weak, solar rays reach the surface without any filter, and the world is exposed to aggressive waves of radiation. The potency of the sun around the planet is so great that harmful particles affect the surface even at night.

The only relief for the native species comes with the long periods of darkness caused by dense fog that can linger for weeks. In these periods, the high, dense fog banks act as a barrier for the aggressive sunlight and provide the planetary surface with a gloomy, rather eerie appearance. During these phases, some of the planet's creatures creep out of their lairs in search of food or mates. Some of the native beings have developed bioluminescent properties enabling them to adapt to the harsh environment. One of the more spectacular natural phenomena of Geonosis is the torrential rain that falls on the planet.

The rainfall occurs only very rarely, but when it does, it usually causes massive flooding. The planet's magnificent canyons and cliffs are proof of the erosion caused by these powerful downpours. Among the desolate features of the landscape are peculiar spires rising high above the ground. These are, in fact, the only visible parts of the huge underground hive-colonies where the native Geonosians live. These intelligent, insectoid beings live in complex maze-like dwellings that extend for thousands of meters underground. These structures imitate the natural forms of the surrounding terrain and so merge perfectly with the arid landscape. Most Geonosian creatures are reptilian or insectoid in form. Among its life-forms are the massifs - huge, dog-like reptiles that can also be found on nearby Tatooine. The Geonosians tame these creatures and keep them as pets as well as to keep their hives free of vermin and other intruders. Another Geonosian species is the red rock algae. These micro-organisms cling to the terrain and give the planetary surface its peculiar hue.