We started by reading Planting a Rainbow by Lois Ehlert. The book is a great introductory to spring as it talks about planting a garden and growing flowers. We use it as a basis for discussion of colour.
After the story we create our own rainbows by following the colours in the book. Unifix cubes are great for learning about patterns and sequences. Our rainbows need 1 red, 1 orange, 1 yellow, 1 green, 1 blue, and 1 dark blue (but we pretend it's purple!). This activity allows the kids to practice their colour identification and their ability to reproduce a pattern. It's been really cool to see just how many of our kiddos can do this independently!
We finish our classroom time with this cute rainbow craft. The kids glue on the precut strips and then cover the paper plate in cotton balls to look just like a cloud.