Actually, I don't think there was much effect, if any, from Halloween because the fall DD is usually early for that. It was in early Sept., but as Disneyluvr2 said it was really hot both this year and last. We're used to heat but we were still finding it very tough to be out in those temps, which were ~100º both years we went. The crowd level was not too bad but spring is really the main event for Dapper Day so there are a lot more activities then. However, it's also crazy busy from what I've heard. Lots of other events coincide with spring DD and it's on a Sunday, whereas the fall DD is on a Friday.