More schools will start classes after Labor Day next fall.
Governor Granholm signed a bill requiring the later start.
Districts that still have teacher contracts in effect next fall will be allowed to delay the change until contracts expire.
The change is intended to help the state's tourism industry by allowing families to take vacation later in the summer.
Granholm says she is not worried over sacrificing education for tourism. She said the state can be successful in both.
Schools still will be required to have nearly eleven-hundred hours of instruction.
Granholm says she would rather see districts keep 180 days of instruction rather than make the school day longer.
But she says districts have the flexibility to do what they want.