Or a storytime for any rainy time actualy. There is no avoiding all those beautiful flowers coming up! "April showers bring May flowers."
My Red Umbrella, by Robert Bright. As in years past, I like to start with our flannel board version of this simple story with lots of opportunities for animal identification and counting.
Rabbits & Raindrops, by Jim Arnosky. Short and gentle, his is a lovely, realistic book about wild rabbits taking shelter during a rain shower.
Thirsty Thursday, by Phyllis Root, illustrated by Helen Craig. This is a cute and silly fantasy about a girl tickling clouds to make them rain. Very short, there's not much to it, but it was fun to flesh out the program.
Move Over, Rover! , by Karen Beaumont, illustrated by Jane Dyer. Cumulative, patterned story about animals crowding into a dog house during a storm. Good for animal identification.