... Jupiter's Colorful Clouds . ... Credit Copyright: Voyager Project , JPL , and NASA Explanation: What makes the colors in Jupiter's clouds ? With a mean temperature of 120 degrees Kelvin (-153 degrees Celsius) and a composition dominated by Hydrogen (about 90%), and Helium (about 10%) with a smattering of hydrogen compounds like methane and ammonia, astronomers have been hard pressed to explain the blue, orange and brown cloud bands and the salmon colored "red" spot. ... NASA Official: Jay Norris. ...