The rules are short enough to post here, so here they are directly from the game box.
OBJECT: To be the first player to move from Start to Finish.
PLAY: Each player decides whether he wants to be a duck or a cat. The first player places his playing piece on the starting space for ducks, if he has a duck, or on the starting space for cats, if he has a cat. He then spins the big umbrella and moves his playing piece counterclockwise to the next space of the color indicated on the spinner.
Cats can only move to spaces under umbrellas and ducks can only move to the rainy spaces. For example, if a player who has a cat playing piece spins red, he can move forward, in this turn, only if the next red space is under an umbrella. If it is not, he cannot move at all and must wait until his next turn.
Play passes to the left, and players advance whenever they spin the color of a space to which they are allowed to move. Whenever a player spins the color that matches the color on his playing piece, he may spin again. A player must spin the correct color to land on Finish.
The first player to reach Finish is the Winner.