So I have a client who wants a wedding cake for the end of July, I live in WI and July for us is the hottest month of the year and can be pretty humid. She is interested in SMBC, but I am concerned with how stable that icing will be if the day is in fact very hot and humid. I have just recently started offering that particular icing and have really only used it on smaller cakes for indoor events. Will this icing be stable enough to sit outside for a couple hours? I am thinking the cake will need to come to temp in the house before being moved outdoors so that it does not sweat. My other option would be to use my regular american buttercream that is made with shortening and butter. I could possibly use fondant, but she would like white chocolate fondant, so that might also have problems outside... Any advice would be great! Thanks!

Honestly I would just tell her that frosting is not conducive to the weather. Just tell her that it's not stable for what she wants. Let her taste some examples of your frostings that WILL work in that weather. Tell her those are her choices. That's what I do.

I agree. SMBC isn't going to hold up. I use Indydebi's buttercream receipe. It's amazingly good for an all crisco based buttercream and it hold up in our 100+ degree summers. That's the only icing I'll use in the summer months

Thanks for the reply ladies! That is what I thought, but I wanted to check with others that may have more experience with SMBC.