Diff states have diff start times. FL -well, my county- started Aug 10th.
Back in the day, kids only had 3 days off for Thanksgiving and a week at Christmas. Now they get the full week of Thanksgiving, 2+ weeks at Christmas, a full week sometime between Feb and April (Spring break), plus all the little one day holidays in between. They still go to school for 180 days, but the rest is extended days off.