Both!!! We go when the kids get out of school and then when they have their Fall break in mid-October. May does seem a little less humid, but the crowds are about the same. The Northern schools are not out yet, but you get lots of Southerners in May trying to get a trip in before it gets too hot. October break time for us is a traditional break time in the South, so you get lots of Southerners during this time too. Both times allow you to visit the waterparks and not freeze. Love the Halloween festivities in October, but the Flower festival decorations are not to be missed. Clear as mud yet? We also go in February and November and this year we have added April, so we obviously aren't particular. Enjoy your decision and your trip.