ATMOSPHERE Neptune's atmosphere is composed mainly of hydrogen, helium, and trace amounts of methane, lending it a vibrant blue hue. High-speed winds, reaching up to 1,500 mph, create massive storms like the Great Dark Spot. The upper atmosphere exhibits dynamic cloud patterns, with white clouds of methane ice and darker storm systems. Extreme temperatures, averaging around -330°F (-201°C), coupled with its turbulent weather, create an atmospheric environment characterized by a mysterious and dynamic outer appearance.