how long is a semester of school
That is unusual to have such short semesters! In the U.S., most texts are scheduled for a 36-week school year, and many states require 180 school days, which works out to two 18-week semesters. Colleges usually have shorter semesters (16 weeks -- 15 weeks of classes + 1 week finals). Since our DSs had many friends at schools, we tended to follow the school district's semester schedule and vacations, although we took an extra week at Christmas so we started a week earlier.