We've been in Late April/Early May, September, January, and May. Looks like May is our favorite, so that's when we're going back. I think I like it best because we go a few days before the end of school--so DS isn't missing much, the weather is good, and the parks aren't too crowded yet. January was GREAT for crowd control, but I didn't like wearing gloves, hats, and sweats. September was AWESOME for low crowds and great weather, but DS missed a week of school, right at the beginning of the year, and that doesn't sit so well as they get older. So May it is!!!