Hello Elizabeth! Welcome to the Disney Parks Moms Panel.
When my family attended
Mickey's Not-So-Scary Halloween Party this past August, we had to cover up our costumes with ponchos from the rainy weather. Like regularly-scheduled Theme Park days, neither rain nor snow stops Mickey and the gang from celebrating the Holidays!
Walt Disney World Resort seldom closes due to inclement weather. While some attractions cannot continue operating when thunder and lightning are present, it is mostly business-as-usual at Walt Disney World Resort. The policy for rainy weather during
Mickey's Very Merry Christmas Party is to keep as much of the party going as possible.
In heavy rain, you will hear updates and can inquire with Cast Members if and when the Holiday Wishes Fireworks Show or Once Upon a Christmastime Parades are cancelled, but with the sporadic nature of weather in Florida, delays are common and entertainment will usually continue once the weather subsides.
I recommend that you keep updated on the weather before your visit and dress according to the forecast. I always bring a park bag with ponchos, umbrellas and extra socks so that my family and I can keep the party going even when the weather gets wet.
Have a Very Merry Visit!
~Todd