If the weather is very hot, or if you know that your cake will be displayed outdoors, you may want to consider using the Wilton recipe for buttercream, which uses Crisco (vegetable shortening) instead of butter. It will definitely hold better – you can always add a butter flavoring to enhance the taste.
Butter, gives the buttercream a very nice flavor and texture, but it is a disaster in hot weather. I live in Florida and the weather can be brutally hot – so I always put my cakes (even the fondant ones) in the fridge overnight – I take them out a couple of hours before delivery to allow for the fondant to air dry and then get on my way… doing this keeps the inside of the cake cold/cool during transport and I avoid having the buttercream inside melt.
Hope this helps.
DJ - Fun Fiesta Cakes
