Significant wave height is an average measurement of the largest 33 % of waves. We measure it because, in many applications of wave data, larger waves are more "significant" (important) than smaller waves. For example, the larger waves in a storm cause the most erosion on a beach.
Significant wave height measured by a wave buoy corresponds well to visual estimates of wave height. This is because most human observers tend to over-estimate the real height of waves. As the significant wave height is an average of the largest waves over a recording period, it should be noted that some individual waves might be much larger than this.
The graph below shows the significant wave height recorded by the Canterbury wave buoy over the past week. You can also, in the graph below this one, see the wave height for the past 60 days.
Wave height this week
Wave height the past 60 days
