In West Virginia, where I grew up, if Halloween falls on a weekend night, trick or treat night is held on the Thursday before. The reason has to do with kids having to get to bed for school the next day, and so would not be out late, playing pranks or engaging in vandalism.

Here where I live in North Carolina, that doesn't happen, although when Halloween falls on a Sunday, trick-or-treat night will often unofficially occur on Saturday due to fundamentalist religious sensibilities. (A lot of folks don't mow grass on a Sunday here, either.)