Ahundred-year wave is a statistically projected water wave, the height of which, on average, is met or exceeded once in a hundred years for a given location. The likelihood of this wave height being attained at least once in the hundred-year period is 63%.[1] As a projection of the most extreme wave which can be expected to occur in a given body of water, the hundred-year wave is a factor commonly taken into consideration by designers of oil platforms and other offshore structures.[2][3][4] Periods of time other than a hundred years may also be taken into account, resulting in, for instance, a fifty-year wave.[5]
Various methods are employed to predict the possible steepness[6] and period[7] of these waves, in addition to their height.