Neptune's surface is both cold and windy. Satellite data reveals temperatures of approximately -360 degrees Fahrenheit and wind speeds that can exceed 1,300 mph, making it the windiest planet in the solar system, according to the Universe Today website.
Neptune's turbulent weather is not fully understood, and scientists are not sure why larger planets have comparatively tamer weather. Some argue that Neptune's smoothness plays a role and that its low friction prevents wind speed from dropping.
Weather on Neptune differs fundamentally from weather on Earth and the other rocky planets. Like Jupiter, Saturn and Uranus, Neptune is a gas giant and is composed primarily of hydrogen. Attempting to stand on Neptune would result in falling through most of the planet. The nature of Neptune's core is unknown, but it is believed to have roughly the same mass as Earth.
Neptune's weather changes at lower altitudes near its core. While nobody knows precisely what the wind speeds are like in its interior, Neptune's massive gravity creates high pressure closer to its core, causing its temperature to rise significantly. A journey to the planet would be turbulent; Neptune would pelt travelers with icy water, methane and ammonia at high, damaging speeds, making prospects of a satellite descent with current technology dim.