Is Neptune the coldest planet?

As the eight planet from our Sun, it is now the outermost planet in the Solar System, and hence the coldest. Orbit and Distance: With an average distance (semi-major axis) of 4,504,450,000 km (2,798,935,466.87 mi or 30.11 AU), Neptune is the farthest planet from the Sun. read more

With Uranus at an average distance of 2.88 billion kilometres from the Sun and Neptune at an average distance of 4.5 billion kilometres it would be very easy to point out which of the gas giants is the coldest, but if you were you were to say that Neptune was the coldest, you’d be wrong. read more

Well, while that makes sense, you'd only be partially right. It depends upon how you define "coldest." With Pluto out of the race, the farthest "real" planet from the Sun is Neptune. read more

Neptune is dark, cold, and very windy. It's the last of the planets in our solar system. It's more than 30 times as far from the sun as Earth is. Neptune is very similar to Uranus. It's made of a thick soup of water, ammonia, and methane over an Earth-sized solid center. Its atmosphere is made of hydrogen, helium, and methane. read more