The last day of school depends on how many snow days we have. When the 2007-2008 school year calendar was originally set, Friday June 13 was identified as the "Earliest Last Day of School." If there were no snow days, then school would indeed end on June 13. However, we have had four snow days so far this year. So at this point, the earliest last day of school is Thursday, June 19. If we have any more snow days (perish the thought!), then that day will change again. The monthly calendar on the ARHS website is updated for each snow day and shows the correct dates for exams in June.

SOURCE: http://www.arps.org/hs/FAQ/