Hello, Patti,
What a wonderful treat to visit Walt Disney World with your grandchildren; you'll be making so many unforgettable memories together!
Mickey's Not-So-Scary Halloween Party is so much fun, too. My family truly enjoyed trick 'n treating throughout the park when we've gone to the party.
While the dates for 2016 have not been released yet, last year the party began on September 15, 2015. With that in mind, it is likely the party will begin on a similar date this year. Last year, the dates were released toward the end of February on the
Disney Parks Blog, so I would check either of the links I provided for news and updates about the party. I'll be keeping my fingers crossed!
Wishing you and your family a magical trip! If we can help with any further questions, please let us know. -
Kara