When does Six Flags Waterworld in Concord open?

Six Flags Hurricane Harbor Concord (formerly Waterworld California or Six Flags Waterworld) is a water park in Concord, California. It is owned and operated by Six Flags Entertainment Corporation. It is the largest water park in Northern California and features over 35 rides, slides, and attractions. The park is open seasonally, from late May to early September, and closed during winter months.