The average temperature on Mercury is 332 degrees Fahrenheit. The hottest temperatures on the planet can reach 801 degrees Fahrenheit, and temperatures can drop to as low as -279 degrees Fahrenheit.Continue Reading
Mercury is the closest planet to the sun, orbiting an average of 36 million miles from the star. This is partially the reason for extremely hot temperatures; however, Venus, the second-closest planet to the sun, actually has a higher overall temperatures, with an average of 864 degrees Fahrenheit. This is partly due to differences in atmosphere. The atmosphere surrounding Mercury is extremely thin, which makes the atmospheric pressure similar to a vacuum. As a result, the heat radiating from the sun disappears into space, as the thin atmosphere cannot hold the heat. Venus' atmosphere is extremely thick, which traps the heat closer to the planet.
Location and rotation are reasons for the extreme difference between Mercury's hot and cold sides. The planet rotates very slowly, completing a rotation once approximately every 60 Earth days. Mercury also has no tilt, so its different hemispheres do not experience a lot of weather changes, such as the planet Earth experiences when seasons change. Mercury has an extremely eccentric orbit, however, that results in some temperature variation during the course of its revolution around the sun.Learn more about Astronomy