Here in Hawaii, local surfers traditionally report wave sizes smaller than elsewhere.

While the rest of the world calls a wave five-footers, those same size waves in Hawaii will typically be dismissed as three-footers.  Something to keep in mind when talking to locals about surfing or wave sizes at various breaks in Hawaii.

The weather service forecasts in Hawaii are based on the international standard of full-face value, measured from the trough in front of the wave to the top of the wave crest. In simplest terms: the front of the wave.

But when Hawaiian surfers look at a wave across the water, they calculate from median sea level to the crest. In simplest terms: the back of the wave.

The wave reporting system in Hawaii changed in April 2001, when the weather service finally convinced observers to report the full-face value of waves, but surfers haven't totally given up local style measurements.