After looking at the weather on Venus and Mars the past two days, the weather on the other inner planet, Mercury, is disappointing by comparison. The innermost planet has no atmosphere and, therefore, no weather. Mercury also has very little axial tilt, so it has no seasons. It also rotates very slowly, so it experiences three days about every two years. Because it has no atmosphere, it has very little heat retention. In the daytime, the rocky surface of Mercury heats up to around 800 degrees Fahrenheit, but at night it cools to around 300 below. Because Mercury has no atmosphere, it has no clouds, no wind, and no precipitation of any kind. If a person could stand on its surface and look up, the sky would be black and stars would be visible except near the blinding light of a huge sun. The day would bring vaporizing heat followed by intolerable cold at night.
