It's Up to You, Griffin! by Susan T. Pickford illustrated by Marcy Dunn Ramsey

Mother Nature chooses Griffin to be the one to inform everyone that it is spring.  He wakes up and sees a shadow which he thinks is a monster (it is really his shadow) and goes back to sleep for a few weeks.  His sense of duty encourages him to try once more and he fulfills his promise.
The illustrations are adorable and includes some cut-aways of animals sleeping.
I did not care for the "mother nature" aspect.