High school typically starts in early August or late July in the United States. The exact start date varies by state and even by district, but this timeframe is common across the nation. The reasons for this early start are multifaceted, including the need to accommodate a full academic year, comply with state requirements, and align with the calendar year.

One primary reason for the early start is the academic calendar. Many high schools follow a traditional calendar that spans from late August to early June, which totals approximately 180 days of instruction. This schedule is designed to meet state requirements for the number of instructional days and to provide students with a full academic year. By starting school in early August, districts can ensure that the academic year concludes before the end of June, allowing for a summer break that aligns with the calendar year.

Additionally, the early start is influenced by the need to prepare students for standardized testing. Many states require students to take standardized tests, such as the SAT or ACT, which are typically administered in the spring. By starting school early, districts can provide students with ample time to prepare for these exams, which are critical for college admissions and scholarships.

Data from the National Center for Education Statistics (NCES) supports the trend of early school start dates. According to the NCES, the average first day of school for public schools in the United States is August 16th. This data indicates that the early start is a widespread practice across the nation.

Moreover, the early start is also influenced by the desire to minimize the impact of summer learning loss. Research has shown that students can lose up to two months of academic progress over the summer break. By starting school early, districts can help mitigate this loss and ensure that students maintain their academic gains throughout the year.

In conclusion, high schools in the United States typically start in early August or late July. This early start is driven by the need to accommodate a full academic year, comply with state requirements, align with the calendar year, prepare students for standardized testing, and minimize summer learning loss. Data from the NCES confirms that this is a widespread practice across the nation.