Trick Or Treating on Halloween will sometimes begin as early as 5:30 PM for toddlers and young kids 6 and under.
So if you're giving out candy on Halloween you can sometimes expect toddlers and younger kids as early as 5:30 PM to 6:00 PM and for the older kids they usually start around 7:00 PM and then continue trick or treating until as last as 8:00 PM to 8:30 PM
Of course it can vary from location to location but that's how it is around here.