The Cloud Book (1975) reads like a nonfiction book. Tomie dePaola's creative genious is in illustrating clouds in interesting ways while labeling each type. For example, one one page, a white horse stands in a field looking up at clouds in the sky and the text reads "Cirrus clouds are white and feathery and they are the highest clouds. They are sometimes called 'mares' tails.'" This is not a narrative with a plot. It's a teaching tool that welcomes young children into a scientific topic. There's even a cloud index on the last page (which is curious because there are no page numbers.)
Greta Lewis has a Cloud Flap Book .Sarah Calvert has a Cloud Viewer. Juana Lopez has a Types of Clouds Poem.