The Planet Quiz Show

Venus has the hottest surface temperature (+864° F). Its very thick carbon dioxide atmosphere and sulfuric acid clouds act as a heat trap. This is called the greenhouse effect. Neptune, because of its distance from the sun, would possess the coldest atmospheric temperatures (-364° F). The general rule argues that the farther away a planet is from the sun, the colder its surface or cloud top temperatures will become. The exception in our solar system is Venus. The table that follows this answer provides an easy way to remember the general surface temperatures of most of the planets. In the table the real surface or cloud top temperatures of the planets can be found below the bold-faced temperatures, which may be easier to remember.

This Mariner 10 photo of Venus reprocessed by Calvin J. Hamilton shows Venus in its natural colors. The yellow is the result of sulfuric acid clouds and haze high in Venus' atmosphere. The air on Venus is almost pure carbon dioxide, and it is so heavy that it would crush you if you were standing on its surface. Then there is the matter of temperature. Venus' temperature is about 850 degrees Fahrenheit on its surface, the hottest surface temperature of any planet in the solar system. Don’t go to the Venus’ North or South Poles for relief. The temperature is the same everywhere on the planet, including the nighttime side of Venus. Venus is not exactly the place on which you would want to raise your kids. Venus would cook, crush, dissolve, smother, and kill you real fast. Astronomers call Venus the sister planet of Earth, because Earth and Venus are about the same size. I'll bet you never had a sister like that!

The last four planets in the solar system do not have any solid surfaces to stand upon. The temperatures of these planets must be measured in their atmospheres. The coldest planet in the solar system is the one that is farthest from the sun, Neptune. Its cloud top temperatures are nearly 400 degrees below zero on the Fahrenheit scale. NASA/JPL/Voyager 2 photo...