File:Ammonia clouds gas giant.jpg

English: Gaseous giants with appearances dominated by ammonia clouds or class I gas giants are found in the outer regions of a planetary system. They exist at temperatures less than about 150 K (−120 °C; −190 °F). The predicted Bond albedo of a class I planet around a star like the Sun is 0.57, compared with a value of 0.343 for Jupiter and 0.342 for Saturn. The discrepancy can be partially accounted for by taking into account non-equilibrium condensates such as tholins or phosphorus,which are responsible for the coloured clouds in the Jovian atmosphere, and are not modelled in the calculations.The temperatures for a class I planet requires either a cool star or a distant orbit. The former may mean the star(s) are too dim to be visible, where the latter may mean the orbits are so large that their effect is too subtle to be detected until several observations of those orbits' complete "years" (cf. Kepler's third law). The increased mass of superjovians would make them easier to observe, however a superjovian of comparable age to Jupiter would have more internal heating, which could push it to a higher class.As of 2015, 47 Ursae Majoris c and d could be Class I planets. Upsilon Andromedae e and 55 Cancri d may also be Class I planets.