User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-3146930-20130819214754/@comment-3146930-20130820093039

Sorry, June 5th. Anyway, in The Son of Neptune, at one point Frank says that he was hoping his godly parent would have shown him a sign on his birthday, which he says was 2 weeks ago. Percy arrives at camp on June 19th, so Frank's birthday would be on the 5th.