Walt Disney World is one of the busiest tourist destinations. There are tens of millions of guests each year. So it will be crowded when you go. But you do have some control over how crowded it will likely be. There is one ultimate rule above all others when it comes to crowd size. When school is out, it will be most crowded.

Families with small children are best able to take advantage of smaller crowd sizes. I have found the absolute best time is during September and early October. Columbus Day is a sneaky Holiday in October that you want to avoid. Other than that, late summer, early fall, is certainly the best time to visit Walt Disney World. Most schools are just starting up and most people have finished their summer vacations. On another note, the weather in Florida in September and October is wonderful. The heavy rain days are likely over, and it is still hot but not oppressive. Once November begins, the crowds slowly start to increase until December when it gets real busy again.
We traveled to Walt Disney World several times during October and November before our children were enrolled in school. Once they were, we did not feel comfortable taking them out for a vacation to Disney World. We have since realized that was probably a mistake. We went to Disney World in August a few years back. It was really hot and it rained a bunch. We lost almost half a day one night because it became a wash out. We did not want to repeat that. It is a balancing act and a parenting decision that won’t be right for everyone. But we would prefer less crowds, better weather and an overall better vacation. In the whole scheme of life, we don’t think missing a few days of school will have an effect on their education. And trips to Walt Disney World are most magical with your little ones, and they are only little for a little while.