Every summer, Joe Kuehn takes his family on vacation, making plans that get his daughter back in time for classes at Countryside High. This year, the Pinellas County School District threw Kuehn for a loop. Months after adopting its 2016-17 academic calendar, the School Board moved its first day of classes two weeks earlier, and to a Wednesday."I don't think we're going to be the only family who didn't plan for that," Kuehn said. "They kind of did it without thinking what the families may or may not have planned. I'm kind of upset about it."The Pinellas school system was not alone in changing its 2016-17 schedule to an Aug. 10 start, cutting summer break short in the process. Hillsborough and Hernando counties also will resume Aug. 10, while Pasco students will return Aug. 15.GETTING READY: Click here to see more of the Times' back-to-school coverage for 2016-17.They're kicking off earlier than they have in years, after state lawmakers ended the mandate that schools could not start classes sooner than two weeks before Labor Day.District leaders asked for a law change in 2014, when confronted with a late Labor Day that would force them to hold off classes until the end of August. To get in enough first semester class hours, they would have to end the period after winter break — something most officials did not want to do.They liked the clean break of the semester at winter vacation, so students could start fresh in the second semester without having to study over the holidays.To that end, many superintendents and school board members asked lawmakers to detach the first day of school from Labor Day. Instead, they suggested tying the bell to the third week of August.That way, they reasoned, the calendars could become more consistent instead of depending on a holiday that changes from year to year.Complicating matters, though, were a handful of "high achieving" districts that were exempt from the law. Their leaders proposed an earlier start date, noting they had already planned to bring students back sooner in the month. House members heeded that request, and suggested a start date of Aug. 10 or later. That proposal lasted through rounds of negotiations with senators who put forth the third week of August for the return to classes.The new rules were in place by mid 2015, and districts could have implemented them to avoid ending the first semester in January 2016. But given the lateness of the Legislature's decision, most chose to wait.Instead, they applied the new start date for 2016-17, adopting updated calendars in the fall. Summers got shorter for children and teachers all over Florida.Some districts went straight to the earliest day available. Others did not.The Pasco County School Board, for instance, set Aug. 15 for students to come back.Pasco schools lobbyist Spencer Pylant explained that the district for several years had resumed classes on the third Monday of August, and that's what Aug. 15 is. Officials rejected starting on Aug. 10 because it's a Wednesday, and "it's hard to get attendance" when beginning mid-week, Pylant said."The third Monday seems to work," he said. "It's not too aggressive one way or the other."Statewide, students in 40 of Florida's 67 districts are slated to begin the school year on Aug. 10, 2016, according to the Department of Education. Seventeen districts will begin Aug. 15, and three — Broward, Miami-Dade and Sarasota — will start a week later. The regular school year ends as early as May 19, 2017, for students in one district, Hamilton County, and as late as June 8, 2017, for students in two districts.With the calendar shifts now in place, families should see longer summer vacations again in 2017. But they'll still need to keep track of the first day of classes each year, and plan accordingly.Contact Jeffrey S. Solochek at [email protected] or (813) 909-4614. Follow @JeffSolochek.