I don't know but they are. So many different kinds. I love them, most of them, most of the time. Some can be boring. But mostly they're magic. Soaring cumulo-nimbus, moody stratus. The low-slung fast moving night clouds sliding overhead right now are definitely magic. I'd say we're pretty lucky to live on a cloud-graced planet. Imagine a world without them, a blank skied orb of rock. T'would be a sad thing.