U is for Umbrella. I write this post on a rainy day in Athens. Umbrellas are out for the purpose of protection from the rain. Where I teach, in Sri Lanka, children are very familiar with umbrellas as they also serve the purpose of protection from the intense equatorial sun.
Three or more large circles can represent a rain cloud. I show the children that a crescent is made by covering a portion of a circle by another circle- then cutting away the extra:
Children can draw a handle and raindrops.