This is going to sound like a real corney question, but I'm making my daughter's PRE-K graduation cake for her class. It is in June and will be outside in the playground. My question is, it it is really hot that afternoon, will the buttercream melt? Is there anything I should do to for having it outside?

You might want to make your BCI with all Crisco to make it more stable. The butter will definitely soften in hot weather, and in some cases the icing can slide off.

It never did for me. In CA in the middle of summer. A 4 tier wedding cake sat out in the direct sun for *hours* w/o a problem. Used 1/2 butter - 1/2 Crisco w/o a problem
If anything instead of melting it got dry.
Bride & family *insisted* I set the cake up around noon in the family's front yard. Not a tree in sight
Found out later the reception didn't start until after 6 p.m.

thanks so much...

Mine doesn't melt either. The recipe I use is in the recipe section "indydebi's buttercream".