I live in Florida and in here is not easy for us to leave cakes in the refrigerator without getting a sweaty mess.
I always leave my cakes in a room with AC after they are finished. But to play it safe I make sure that the fillings we use in tiered cakes are safe to stay out of the fridge 
and won't go bad.

In this tutorial I talk more about it and I show how a basic filling can work with other flavors.

I hope you guys enjoy!