Board Thread:Site Problems and Appearance/@comment-26072045-20150814152310/@comment-5475153-20150816014553

While I agree that we should narrow their birth year, I think it's more likely that "the last day of summer" refers to summer vacation, and not the actual season. According to Piedmont Unified School District's 2012-2013 school calendar, the first day of school after the events of Gravity Falls falls on August 22, so the twins' birthday would fall on August 21.