Cowgirl Kate And Cocoa by Erica Silverman (2009, Paperback, Reprint)

In this fourth book in the series, Cowgirl Kate and Cocoa are ready for rainy-day adventures--or are they? Cocoa's not so sure he wants to get wet. And thunder can be a little frightening. But whatever the weather, these cowpoke pals are sticking together. With snappy text and silly illustrations, Cowgirl Kate and Cocoa are as feisty as ever. So pull on your slicker for a little stormy weather and a lot of splashy fun.