>>2781483
East coast beaches are deposition beds so they have finer sand and calmer waves, plus the upwards current from the gulf stream typically makes the beaches warmer.

On the other side, west coast beaches are near transform fault lines and convergent boundaries so they have more active waves which are better for surfing and cause more erosion which results in coarser sand. In addition the California current draws water from Alaska down the coast so the beaches on average tend to be colder.