Labor Day, the first Monday in September, is a creation of the labor movement and is dedicated to the social and economic achievements of American workers. It constitutes a yearly national tribute to the contributions workers have made to the strength, prosperity, and well-being of our country.
It is a public holiday and so the parks will be busy for that time of year, which is normally quiet. Unlike public holidays in the UK very little closes in the US.
Been there on Labour Day it's busy but nothing like the summer, however the wait times can be as long as the summer as they seem to have less staff and slower loading patterns on the rides. Now that sounds so sad that I notice such things when I'm in Disney!
Labour day is always the first monday in September. it is busrer than usual ithat weekend, but it is not too bad and not as busy as the summer season. It does go quieter afterwards.