We went last year from May 3-11. We were floored at how busy the parks were, most of the days we were there. We had some week day crowds that were worse than we had seen on summer weekend visits of past years. I think part of the problem was there were a crazy amount of refurbs of big rides going on. The big rides that were running, were often down multiple times a day, forcing crowds into smaller areas of the park and other rides. We still had a great time, but were very surprised how crowded it was and how many rides were down for the majority of our visit.