The coldest planet of our solar system is:

Despite Neptune being at the outer edge of our solar system and the farthest planet from the Sun, Uranus boasts the lowest recorded temperature in our solar system, dropping down to -224°C or -371°F. Uranus has a very special atmosphere in that it does not retain heat as well as Neptune does.

• Venus: It is actually the hottest planet in our solar system, with surface temperatures averaging around 464°C (867°F) due to its thick, heat-trapping atmosphere.
• Earth: It maintains a stable, mild average temperature of about 15°C (59°F), which is essential for supporting life.
• Neptune: While it is further from the Sun and has a lower average temperature than Uranus, its minimum temperature (roughly –214°C) is warmer than Uranus's minimum because Neptune generates more internal heat.