Two regional patterns
US K-12 districts split into two broad camps on when the school year starts. The "before Labor Day" camp — predominantly in the South, the Mountain West, and parts of the Midwest — opens the school year in early or mid-August. The "after Labor Day" camp — predominantly in the Northeast and parts of the Mid-Atlantic — opens the day after the Labor Day federal holiday on the first Monday of September.
Why the divide exists
The before-Labor-Day camp grew out of the desire for a balanced school year and the need to finish the spring semester before the deepest heat of late May. The after-Labor-Day camp persists in the Northeast for tourism reasons (extending the summer season for Jersey Shore, Cape Cod, and similar economies) and in some districts for energy-cost reasons (many older school buildings are not air-conditioned and an August start is genuinely uncomfortable).
What this means for printed calendars
If you live in a before-Labor-Day district, print the August monthly calendar early — the first day of school is the most important date of the year and it sits in the middle of the month. If you live in an after-Labor-Day district, print the September calendar instead — the first day of school is the day after Labor Day, and the August calendar shows summer recess only.
The end-of-year mirror
The two start patterns produce two end patterns. Before-Labor-Day districts usually end the school year in the third week of May, in time for the Memorial Day weekend. After-Labor-Day districts usually end in the third week of June, after Memorial Day. The total instructional time is similar; the calendar shape is different.
Mixed households
Households with members in both patterns — common in college towns, military families, and households with split-custody children across districts — should print the academic-year overview for both districts and lay them side by side. The federal holidays are the same; the start and end dates differ. Coordinating across the difference is the planning challenge.