The significant wave height and dominant wave period that is traditionally reported from the offshore buoys. Significant wave height is the average height of the highest one-third of the waves. When both swell and wind wave energies are present, it will equal the square root of the sum of the squares of the swell energy and wind wave energy. Dominant wave period is the period with maximum energy, which may be swell or wind wave energy. Example: A buoy reporting 15 feet at 10 seconds could be monitoring a multitude of different swells to equal 15 feet, but the dominant swell at that location has a swell period of 10 seconds. That does not mean there is a 15-foot swell with a swell period of 10 seconds, although it could. Best bet would be to use Surfline's LOLA buoy information to decipher exactly the size and energy of each swell.