My answer would be somewhat the same.
Our needs start in May because we have to set up the program for the summer. We generally hire our students starting in May. They then work on a part-time basis, particularly on weekends. Starting in late June, when school is out, they can work full time until late August.
So our full-time weeks are in July and August. Before that, we need to have the option of having them work part time to prepare the program. However, somewhat as Mr. Cantin said, we're stuck with the program requirement of a minimum of 30 hours per week. However, you can't have students who haven't completed their school year work 30 hours a week. That doesn't work.