Sec. 10-16. Length of school year. Each school district shall provide in each school year no less than one hundred and eighty days of actual school sessions for grades kindergarten to twelve, inclusive, nine hundred hours of actual school work for full-day kindergarten and grades one to twelve, inclusive, and four hundred and fifty hours of half-day kindergarten, provided school districts shall not count more than seven hours of actual school work in any school day towards the total required for the school year. If weather conditions result in an early dismissal or a delayed opening of school, a school district which maintains separate morning and afternoon half-day kindergarten sessions may provide either a morning or afternoon half-day kindergarten session on such day.
Generally, 180 days is what is required of school and when they have a delay opening or an early dismissal it DOES COUNT toward the 180 days.
As long as there is 1/2 day, it counts the same as an entire day. Even if YOU must be late as long as your child is in school before 1/2 of the day has passed, your child will be counted tardy, but not absent. Also, if you must pick your child up early from school, as long as it is after the 1/2 day mark, it will not be counted as an absent or a tardy.