How early do kids start school?

The American Pediatric Association recommends that middle and high school students start school no earlier than 8:30 am to protect their physical and mental well-being.[1] To understand the extent to which students face early school start times in California, we gathered and analyzed publicly-available information from school district websites. We found that that the vast majority of middle and high schools in the State subject their students to unhealthy start times.  We present some findings from our research below. 

Our database includes start time information for over 70 percent of the schools in California, and includes details on school characteristics, such as region, school size, racial composition and type (i.e. traditional, charter or alternative) and region, and by the availability of zero period times (organized activities for students prior to the official start of the school day).

The graph displays the cumulative distribution of California school start times by school level.

  • In 2015-16, 93 percent of high schools in California required their students to start school before 8:30AM.
  • Zero periods, which were used by 37 percent of the high schools and 17 percent of  the middle schools in the database, play a large role in driving start times earlier.  For example, 45 percent of high schools set zero periods that asked students to arrive at school before 7:30 am. When zero periods are excluded, the percentage of high schools with start times before 7:30AM falls to 10 percent.
  • Start-time differences found across school and district characteristics demonstrate that students do not have the same access to healthy start times.
  • Among middle and high schools, racial composition is associated with access to healthy start times, and minority students are slightly more likely than white students to attend schools with earlier start times. When we control for other school characteristics, such as school size, region and urbanicity, we find that middle and high school with higher percentages of minority students than white students are more likely to attend schools with start times before 8:30, though the effect is small.
  • More affluent schools are more likely to use zero periods than less affluent schools. When zero periods are included, middle and high schools with lower percentages of students who receive free or reduce lunches are slightly more likely to have start times before 8:30. This relationship persists when we control for other factors that could influence start times, such as school size, geographic region or school racial composition. However, the relationship disappears when we exclude zero periods.


Read more at:

Tseng, F., & Levin, S. (2017, October 9). “How early do kids start school? A Database of K-12 School Start Times in California”.