Neptune is the coldest planet in the solar system. As the planet furthest away from the Sun, Neptune receives less light than the other planets.
Neptune became the coldest planet in the solar system in June of 2008 when Pluto lost its status as a planet. Until then, Pluto was considered to be the outer-most planet in the solar system, which also made it the coldest. According to NASA, Pluto is now classified as a dwarf planet. Neptune is located 2.8 billion miles from the Sun and its surface temperature often falls as low as 72 Kelvin or -201 degrees Celsius.