what is coldest planet
1. The Coldest Planet Is Neptune. As the planets in our Solar System get further away from the Sun, they generally get colder. So what is the coldest planet of our Solar System. That would be Neptune, the 8th and final planet in the Solar System. If Pluto was still a planet, it would be colder, but now it's Neptune. 2. The Hottest Planet Is Venus. It is the hottest planet in the solar system.