So here are my picks for this challenge, I hope you enjoy! :)
We will start with the summer since that is the season we are in now:

This book is summer time for me here in Kansas. We get to spend our warm, humid nights with these little lightening bugs, it makes for beautiful scenery and they don't tend to mess with you, they just give you a pretty show, they are performers of the best kind, I'd say ;)
From here we will go in order, so next is Autumn, my favorite season!

It rains a lot here in the Autumn and the leaves are beautiful when they are changing, so this was the best depiction of fall for me!
Winter is next:

We don't tend to get a ton of snow, but we do get some and most of the houses are decorated similar to this for most of the winter season, so this was a good cover to depict how winter is for us here.
And finally Spring, my other favorite season:
I grew up spending a ton of time on my grandparents farm especially during the summer and granted we didn't have a swing like this, we still had so much fun and this swing reminds me of fun that can be had when you are growing up. So, this is my spring book cover.
