Planet with the Lowest Atmospheric Temperature

Uranus is an ice giant without a conventional solid surface on which a surface-air temperature could be defined. The 49 K figure is a local atmospheric minimum, not the planet's global mean temperature or a surface temperature.

NASA notes that parts of Uranus's atmosphere are colder even than Neptune's, although Neptune orbits farther from the Sun. The record therefore concerns an observed atmospheric extreme, not a ranking inferred simply from distance to the Sun.

The atmosphere consists chiefly of hydrogen and helium, with methane and traces of water and ammonia. Methane absorbs red light and contributes to Uranus's blue-green appearance, while its atmosphere also exhibits rapidly changing clouds and strong winds.