According to the press release from Delta when it announced the 330 IGW purchase, it says: "The 10 A330-300 aircraft will augment Delta's existing fleet of 32 A330s. The first A330 delivery is scheduled for spring of 2015, with three additional airplanes scheduled for that year, four in 2016, and the final two in 2017."

Spring is a large timeframe usually between March and June right?