When I was growing up, the official end to summer in Cleveland Heights and University Heights was Labor Day. We had a pretty regular school calendar that started after Labor Day and ended in mid-June. This was the same for almost all school districts. In some states, this calendar is still the norm. As of the 2016–17 school year, CH-UH started back to school two weeks before Labor Day. Cleveland Schools start even earlier. South Euclid starts three weeks before Labor Day. Why do nearly all school districts in Ohio start school earlier and earlier in August?
No one will admit the real reason, but the only explanation is that beginning the school year earlier in the summer gives more instructional time before state testing.