Venus is famously hot, due to an extreme greenhouse effect which heats its surface to temperatures as high as 450 degrees Celsius. The climate at the surface is oppressive; as well as being hot, the surface environment is dimly lit, due to a thick blanket of cloud which completely envelops the planet. Ground-level winds are slow, pushing their way across the planet at painstaking speeds of about 1 metre per second – no faster than a gentle stroll.
However, that is not what we see when we observe our sister planet from above. Instead, we spy a smooth, bright covering of cloud. This cloud forms a 20-km-thick layer that sits between 50 and 70 km above the surface and is thus far colder than below, with typical temperatures of about -70 degrees Celsius – similar to temperatures found at the cloud-tops of Earth. The upper cloud layer also hosts more extreme weather, with winds that blow hundreds of times faster than those on the surface (and faster than Venus itself rotates, a phenomenon dubbed ‘super-rotation’). … (ESA)