I made one wedding cake in the middle of a heat wave. I had been doing this for about 10 years at that time with some success and was probably getting over confident. We completed the cake and set it up for the outdoor wedding and reception. As I sat watching the ceremony, I noticed that although the cake was in the shade, as the temperature continued to rise, the cake was beginning to tilt. Now, our cakes are supported by cardboard and dowels, but the heat was actually melting the icing! We were able to move it indoors to a cool room and keep it stable, but that was a close call! Soon after, I was living in Greece and discovered that they either used the fondant/royal icing combo or this recipe for a heat impervious experience.