The following language is in the confirmation e-mail: “This experience will go on rain or shine; some attraction experiences may be modified due to inclement weather“
Like with theme park tickets,
MNSSHP tickets,
MVMCP tickets, etc - there is a level of weather risk that we as consumers take when booking these outdoor-dependent events. It’s really buyer beware for the most part.
In reality, there have been very few reports of all out wash outs over the three year history of MK EMM. Has it happened? Sure, but not all that common. But of course, can’t bet on Mother Nature.
Ultimately, if weather is a major issue on your morning that fundamentally impacts the event, it’s not a bad idea to stop by Guest Relations to discuss. Disney has a decent track record of wanting to make things right for guests. Of course YMMV and I still think it’s best to be prepared that curve balls can always happen, but it never hurts.