Each school district in the state has a local school board, which has some discretion in determining the specific start and end dates of the school year, as well as the number of school days.
According to the Illinois School Code, the legal school year must be at least 180 days. However, many school districts choose to add a few additional days to the calendar in order to provide more time for instruction or other activities.
Here are some of the factors that can influence the number of school days in a school year in Illinois:
180 days of instruction, required by state law
Holidays, such as Labor Day, Thanksgiving, Christmas, and Easter
Local events, such as fairs or festivals
Professional development days for teachers
Makeup days for days lost due to inclement weather or other unforeseen circumstances
Extracurricular activities, such as sports or clubs