What kind of wedding cake frosting do i use?

What kind of wedding cake frosting do i use?

Im making a wedding cake for my brother, His wedding is in september..Its outside..The temp is usually around 75-80…im making him carrot cake and i dnt know what kind of icing to use….Cream cheese icing doesnt cover as good as buttercream but i dont want the buttercream to melt..im going to fill the cake with cream cheese icing

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