(a) Except for learning programs during summer, flexible learning year programs authorized under sections 124D.12 to 124D.127, and learning year programs under section 124D.128, a district must not commence an elementary or secondary school year before Labor Day, except as provided under paragraph (b). Days devoted to teachers' workshops may be held before Labor Day. Districts that enter into cooperative agreements are encouraged to adopt similar school calendars.
(b) A district may begin the school year on any day before Labor Day to accommodate a construction or remodeling project of $400,000 or more affecting a district school facility. A school district that agrees to the same schedule with a school district in an adjoining state also may begin the school year before Labor Day as authorized under this paragraph.