Hi, I have a graduation cake to make at the end of May that will be in New Orleans. Originally I was gonna do buttercream until I learned that all the festivities will be outside, so I was thinking instead of using the other fondant I was thinking of making and using marshmallow fondant and my question is will this be able to withstand the HEAT without melting like crazy as if I used buttercream.......Thanks again!!!!!

Yes it will melt. I have trouble with it here in Texas when parties are outside. Good Luck

Indydebbie's buttercream recipe is suppose to hold up very well outdoors in heat and humidity. You might want to PM her and get her opinion. HTH