School Calendar Research
There is no open dataset of American school calendars. They are set by roughly 13,000 individual districts and published as PDFs, which is why questions about them are so hard to answer at any scale. We assemble the data by hand, district by district, from official sources — and these pages report what it shows.
Each analysis states its sources and its limits. The dataset is a deliberately narrow one, and the findings are written to describe it rather than the country.
The analyses answer two questions: how far apart neighboring district calendars really are, and which states set school start dates and instructional time in law. Both are built from the same district and state data that powers the calendar pages.
Analyses
- How Much Do U.S. School Calendars Actually Differ?
An analysis of 16 large U.S. school districts enrolling 3.6 million students: their 2027 spring breaks fall across six different weeks, and in three of four states the districts do not agree with each other.
- School Calendar Laws by State: Start Dates and Required Instructional Time
Which U.S. states set school start and finish dates in law, and how many days or hours each state requires — a 50-state table with statutory citations, and what it explains about why calendars differ.
The underlying data
District calendars are transcribed by hand from each district’s own published calendar. Every district page links to that calendar and shows the date we last checked it. Browse them from the state and district directory.
Enrollment figures come from the National Center for Education Statistics’ Common Core of Data. State calendar law citations come from the Education Commission of the States’ 50-state comparison. Each analysis names its sources and the year of the data.
The district set is a convenience sample. It holds the districts whose official calendars we could retrieve, not a random sample of U.S. districts. Read the findings as descriptions of that named set, not of the whole country.
We audit the data and publish corrections. Read how we source school calendar dates, or tell us about a date that does not match your district’s calendar.