The average temperature on Neptune is -373 degrees Fahrenheit. Neptune is, on average, 2.8 billion miles from the sun, making it the eighth planet from the sun, which is one reason this planet is so cold.
Neptune's upper atmosphere clouds have a temperature ranging from a bone-chilling -240 degrees to -330 degrees, and these clouds are made from methane ice crystals. The coldest temperature ever measured in this solar system was -391 degrees on Triton, one of Neptune's satellites, and the fastest wind speed ever recorded was on Neptune with a speed of 1200 mph around the older Great Dark Spot. The average wind speed around Neptune's equator is 700 mph.