For a geoduck to make it into a river, it must know the sequence and order of water flow. Geoducks usually live in the ocean, not in a river, so they must study the order of water flow in order to determine the best sequence for making it into a river.
After extensive study of the sequence and order of water, the geoduck has determined that June (じゅん) is the best time to travel to the river. June is the best time for the temperature and atmospheric pressure to be just right for such a journey. In June, the geoduck will set out.