This image of Martian clouds illustrates the fact that they are found only in the equatorial region. Click on image for full size version (58K JPG) Image from: Hubble

Unlike the Earth, where clouds are found around the entire globe, on Mars, clouds seem to be plentiful only in the equatorial region, as shown in this Hubble telescope image. This may be because water of Mars may only be found at equatorial regions.

As early as 1796 scientists were reporting "yellow", and "white" or "bluish" clouds in the Martian atmosphere. With data from the Mariner 9 mission, scientists could finally prove that the clouds were made of water. Mars Global Surveyor is providing more proof of the existence of water clouds.

More study is needed to understand just how the clouds come and go in the Martian atmosphere. For example, even though clouds have been found, there is no proof it actually rains on Mars! Precipitation of water depends upon how cold it is. The temperatures in the atmosphere may be too cold for water to fall to the ground as droplets.

As a first step in answering some of those questions, Mars Pathfinder took measurements of many clouds in the Martian sky from the surface of Mars itself. Scientists are studying images of the Martian sky from the 80-day mission. The Mars '98 mission will carry a weather satellite, just like the instruments that are used to bring you the weather on the evening news. Then scientists expect to receive much more complete data about Martian weather.