 Accumulated Cyclone Energy ( ACE ) is a measure of how active a hurricane season is . It is calculated by squaring the windspeed of a cyclone with at least tropical storm @-@ force winds every six hours , summing the results , and dividing that total by 104 . As a tropical cyclone does not have gale @-@ force winds until it becomes a tropical storm , tropical depressions are not included in these tables . For all storms , ACE is given to three significant figures . The ACE in the east Pacific proper ( 140 ° W to North America ) is given ; the ACE in the central Pacific ( the International Date Line to 140 ° W ) is given in brackets . The table includes the ACE for Li and John only during those storm 's time east of the dateline . Their ACE west of the dateline is part of the totals of the 1994 typhoon season . 
