Sailings are often slower out of the U.S. -- the vessels are loading a lot of empty containers by calling multiple ports to maximize the utilization of the vessel. As a result, the sailing schedules for exports from the US are often less frequent with longer transit times. On the bright side, it means that space is easier to secure.
Note: For an LCL shipment, the earliest sailing will likely be 10-14 days after the cargo ready date. It is best to plan ahead!