Neptune is a wintry planet. Its cold atmosphere of hydrogen, helium and methane stretches down to a slushy ocean of water and ammonia. On this icy planet, where the average temperature is -353°F, storms can trigger the fastest winds of the solar system—roughly 1270 mph faster than any wind recorded on Earth. Not only are Neptune’s storms windier than any on Earth, its tempests can be the size of Earth. When Voyager 2, Earth’s one and only mission to Neptune, reached the ice giant in 1989, it saw a storm that big in progress. Is it always a cold and stormy winter on Neptune? Technically the planet does have seasons, and Neptune’s summer, such as it is, lasts 40 years. When one of its poles tips toward the sun, temperatures are about 50 degrees warmer, which is still a few hundred degrees below zero.